Annual report pursuant to Section 13 and 15(d)

Debt - CCH Working Capital Facilitiy (Details)

v3.8.0.1
Debt - CCH Working Capital Facilitiy (Details)
 12 Months Ended
Dec. 31, 2017
USD ($)
CCH Working Capital Facility [Member]  
Line of Credit Facility [Line Items]  
Line of Credit Facility, Maximum Borrowing Capacity $ 350,000,000
Debt Instrument, Description of Variable Rate Basis LIBOR or base rate
CCH Working Capital Facility [Member] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]  
Line of Credit Facility [Line Items]  
Debt Instrument, Basis Spread on Variable Rate 1.50%
CCH Working Capital Facility [Member] | Minimum [Member] | Base Rate [Member]  
Line of Credit Facility [Line Items]  
Debt Instrument, Basis Spread on Variable Rate 0.50%
CCH Working Capital Facility [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]  
Line of Credit Facility [Line Items]  
Debt Instrument, Basis Spread on Variable Rate 2.00%
CCH Working Capital Facility [Member] | Maximum [Member] | Base Rate [Member]  
Line of Credit Facility [Line Items]  
Debt Instrument, Basis Spread on Variable Rate 1.00%
CCH [Member] | CCH Working Capital Facility [Member]  
Line of Credit Facility [Line Items]  
Line of Credit Facility, Maximum Borrowing Capacity $ 350,000,000
CCH [Member] | CCH Working Capital Facility [Member] | Base Rate Determination Federal Funds Rate [Member] | Base Rate [Member]  
Line of Credit Facility [Line Items]  
Debt Instrument, Basis Spread on Variable Rate 0.50%
CCH [Member] | CCH Working Capital Facility [Member] | Base Rate Determination LIBOR [Member] | Base Rate [Member]  
Line of Credit Facility [Line Items]  
Debt Instrument, Basis Spread on Variable Rate 0.50%
CCH [Member] | CCH Working Capital Facility [Member] | Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member]  
Line of Credit Facility [Line Items]  
Debt Instrument, Basis Spread on Variable Rate 1.50%
CCH [Member] | CCH Working Capital Facility [Member] | Minimum [Member] | Base Rate [Member]  
Line of Credit Facility [Line Items]  
Debt Instrument, Basis Spread on Variable Rate 0.50%
CCH [Member] | CCH Working Capital Facility [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member]  
Line of Credit Facility [Line Items]  
Debt Instrument, Basis Spread on Variable Rate 2.00%
CCH [Member] | CCH Working Capital Facility [Member] | Maximum [Member] | Base Rate [Member]  
Line of Credit Facility [Line Items]  
Debt Instrument, Basis Spread on Variable Rate 1.00%
CCH [Member] | CCH Revolving Loans [Member]  
Line of Credit Facility [Line Items]  
Line Of Credit Facility, Unused Capacity, Commitment Fee Percentage Of Margin On Undrawn Commitment 40.00%
Line of Credit Facility, Number of Business Days Notice Required for Repayment of Debt Without Penalty 3 days
CCH [Member] | CCH Letter of Credit [Member] | Portion issued and not drawn [Member]  
Line of Credit Facility [Line Items]  
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage 0.20%
CCH [Member] | CCH Letter of Credit [Member] | Drawn Portion [Member] | Base Rate [Member]  
Line of Credit Facility [Line Items]  
Debt Instrument, Basis Spread on Variable Rate 2.00%
CCH [Member] | CCH LC Loan [Member] | Maximum [Member]  
Line of Credit Facility [Line Items]  
Debt Instrument, Term 1 year
CCH [Member] | CCH Swing Line Loan [Member]  
Line of Credit Facility [Line Items]  
Line of Credit Facility, Minimum Period For Termination Date, Number of Business Days 4 days
CCH [Member] | CCH Swing Line Loan [Member] | Maximum [Member]  
Line of Credit Facility [Line Items]  
Debt Instrument, Term 15 days
CCH [Member] | CCH Working Capital Loan [Member]  
Line of Credit Facility [Line Items]  
Line of Credit Facility, Annual Temporary Requirement, Balance, Outstanding Principal $ 0
Line of Credit Facility, Annual Temporary Requirement, Period, Number of Consecutive Business Days 5 days