Revenue Recognition Contract Liabilities (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Jan. 01, 2018
Revenue Recognition [Abstract]
Contract with Customer, Liability	$ 242,017	$ 242,017	$ 244,658	$ 247,296
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Change in Estimate of Transaction Price	0	0
Contract with Customer, Liability, Revenue Recognized	(2,641)	(5,279)
Other Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Receivables, Net, Current	6,900	6,900		$ 2,500
Performance Obligations Related To Contract Liabilities [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	5,287	$ 5,287
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		6 months
Performance Obligations Related To Contract Liabilities [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	10,566	$ 10,566
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		1 year
Performance Obligations Related To Contract Liabilities [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	10,568	$ 10,568
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		1 year
Performance Obligations Related To Contract Liabilities [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	10,566	$ 10,566
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		1 year
Performance Obligations Related To Contract Liabilities [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	10,566	$ 10,566
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		1 year
Performance Obligations Related To Contract Liabilities [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	10,566	$ 10,566
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		1 year
Performance Obligations Related To Contract Liabilities [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	183,898	$ 183,898
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		1 year
Remaining Performance Obligations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2018-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	850,434	$ 850,434
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		6 months
Remaining Performance Obligations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	1,618,612	$ 1,618,612
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		1 year
Remaining Performance Obligations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	1,515,147	$ 1,515,147
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		1 year
Remaining Performance Obligations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	1,309,562	$ 1,309,562
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		1 year
Remaining Performance Obligations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	1,116,179	$ 1,116,179
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		1 year
Remaining Performance Obligations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	982,445	$ 982,445
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		1 year
Remaining Performance Obligations [Member] | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation	$ 15,885,615	$ 15,885,615
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Period		1 year