Condensed Consolidating Guarantor Financial Statements - Balance Sheets (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Feb. 25, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 343,560		$ 86,655	$ 285,498	$ 93,699
Accounts receivable	780,956		562,214
Due from Related Parties, Current	534		295
Inventories	77,120		49,397
Other Assets, Current	18,711		17,264
Assets, Current	1,220,881		715,825
Property, plant and equipment (net of accumulated depreciation of $648,434 and $607,903, respectively)	3,845,508		3,457,326
Equity method investments	276,893		274,009
Goodwill	334,893	$ 78,768	257,302
Intangible Assets, Net (Excluding Goodwill)	466,934		365,038
Other noncurrent assets	134,847		140,807
Right-of-Use Asset, Operating and Finance Leases	94,082		0
Assets	6,374,038		5,210,307
Current liabilities:
Accounts Payable	750,635		494,792
Due to Related Parties	1,042		3,715
Accrued liabilities	100,941		115,095
Other current liabilities including deferred revenue and current portion of long-term debt	28,025		23,555
Liabilities, Current	880,643		637,157
Long-term debt	2,461,583		2,278,834
Deferred income taxes	142,461		55,789
Other Liabilities, Noncurrent	142,538		38,548
Commitments and Contingencies
Redeemable preferred stock, $0.01 par value, $373,790 liquidation preference (authorized - 4,000 shares; issued - 350 shares)	366,087		359,658
Subsidiary Preferred Stock, Value Outstanding	250,239		0
Stockholders' Equity Attributable to Parent	1,355,214		1,490,832
Stockholders' Equity Attributable to Noncontrolling Interest	775,273		349,489
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	2,130,487		1,840,321	1,620,163	1,658,365
Liabilities and Equity	6,374,038		5,210,307
Consolidation, Eliminations [Member]
Current assets:
Cash and cash equivalents	(1,558)		(4,151)	(4,863)	(8,630)
Accounts receivable	0		0
Due from Related Parties, Current	0		0
Inventories	0		0
Other Assets, Current	0		0
Assets, Current	(1,558)		(4,151)
Property, plant and equipment (net of accumulated depreciation of $648,434 and $607,903, respectively)	0		0
Equity method investments	(4,272,474)		(4,546,932)
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	0		0
Other noncurrent assets	0		0
Right-of-Use Asset, Operating and Finance Leases	0
Assets	(4,274,032)		(4,551,083)
Current liabilities:
Accounts Payable	0		0
Due to Related Parties	0		0
Accrued liabilities	0		2
Other current liabilities including deferred revenue and current portion of long-term debt	0		0
Liabilities, Current	0		2
Long-term debt	(6,458)		(6,315)
Deferred income taxes	0		0
Other Liabilities, Noncurrent	0		0
Commitments and Contingencies
Redeemable preferred stock, $0.01 par value, $373,790 liquidation preference (authorized - 4,000 shares; issued - 350 shares)	0		0
Subsidiary Preferred Stock, Value Outstanding	0
Stockholders' Equity Attributable to Parent	(4,267,574)		(4,544,770)
Stockholders' Equity Attributable to Noncontrolling Interest	0		0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	(4,267,574)		(4,544,770)
Liabilities and Equity	(4,274,032)		(4,551,083)
Reportable Legal Entities [Member] | Parent Company [Member]
Current assets:
Cash and cash equivalents	275,687		40,064	233,282	32,457
Accounts receivable	1		83
Due from Related Parties, Current	166		120
Inventories	0		0
Other Assets, Current	6,633		6,682
Assets, Current	282,487		46,949
Property, plant and equipment (net of accumulated depreciation of $648,434 and $607,903, respectively)	6,956		6,732
Equity method investments	2,839,934		3,267,581
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	3		5
Other noncurrent assets	31,653		41,981
Right-of-Use Asset, Operating and Finance Leases	7,133
Assets	3,168,166		3,363,248
Current liabilities:
Accounts Payable	136		38
Due to Related Parties	6		1
Accrued liabilities	22,087		33,239
Other current liabilities including deferred revenue and current portion of long-term debt	5,245		5,723
Liabilities, Current	27,474		39,001
Long-term debt	1,348,742		1,467,083
Deferred income taxes	63,672		4,882
Other Liabilities, Noncurrent	6,977		1,792
Commitments and Contingencies
Redeemable preferred stock, $0.01 par value, $373,790 liquidation preference (authorized - 4,000 shares; issued - 350 shares)	366,087		359,658
Subsidiary Preferred Stock, Value Outstanding	0
Stockholders' Equity Attributable to Parent	1,355,214		1,490,832
Stockholders' Equity Attributable to Noncontrolling Interest	0		0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	1,355,214		1,490,832
Liabilities and Equity	3,168,166		3,363,248
Reportable Legal Entities [Member] | Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	0		0	0	0
Accounts receivable	650,600		461,980
Due from Related Parties, Current	85		18
Inventories	77,120		49,397
Other Assets, Current	4,845		6,711
Assets, Current	732,650		518,106
Property, plant and equipment (net of accumulated depreciation of $648,434 and $607,903, respectively)	986,165		992,974
Equity method investments	1,709,433		1,553,360
Goodwill	0		0
Intangible Assets, Net (Excluding Goodwill)	117,533		119,583
Other noncurrent assets	4,675		4,788
Right-of-Use Asset, Operating and Finance Leases	6,534
Assets	3,556,990		3,188,811
Current liabilities:
Accounts Payable	689,162		444,984
Due to Related Parties	1,036		3,714
Accrued liabilities	10,319		18,424
Other current liabilities including deferred revenue and current portion of long-term debt	4,583		3,409
Liabilities, Current	705,100		470,531
Long-term debt	6,458		6,315
Deferred income taxes	0		0
Other Liabilities, Noncurrent	6,616		0
Commitments and Contingencies
Redeemable preferred stock, $0.01 par value, $373,790 liquidation preference (authorized - 4,000 shares; issued - 350 shares)	0		0
Subsidiary Preferred Stock, Value Outstanding	0
Stockholders' Equity Attributable to Parent	2,838,816		2,711,965
Stockholders' Equity Attributable to Noncontrolling Interest	0		0
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	2,838,816		2,711,965
Liabilities and Equity	3,556,990		3,188,811
Reportable Legal Entities [Member] | Non-Guarantor Subsidiaries [Member]
Current assets:
Cash and cash equivalents	69,431		50,742	$ 57,079	$ 69,872
Accounts receivable	130,355		100,151
Due from Related Parties, Current	283		157
Inventories	0		0
Other Assets, Current	7,233		3,871
Assets, Current	207,302		154,921
Property, plant and equipment (net of accumulated depreciation of $648,434 and $607,903, respectively)	2,852,387		2,457,620
Equity method investments	0		0
Goodwill	334,893		257,302
Intangible Assets, Net (Excluding Goodwill)	349,398		245,450
Other noncurrent assets	98,519		94,038
Right-of-Use Asset, Operating and Finance Leases	80,415
Assets	3,922,914		3,209,331
Current liabilities:
Accounts Payable	61,337		49,770
Due to Related Parties	0		0
Accrued liabilities	68,535		63,430
Other current liabilities including deferred revenue and current portion of long-term debt	18,197		14,423
Liabilities, Current	148,069		127,623
Long-term debt	1,112,841		811,751
Deferred income taxes	78,789		50,907
Other Liabilities, Noncurrent	128,945		36,756
Commitments and Contingencies
Redeemable preferred stock, $0.01 par value, $373,790 liquidation preference (authorized - 4,000 shares; issued - 350 shares)	0		0
Subsidiary Preferred Stock, Value Outstanding	250,239
Stockholders' Equity Attributable to Parent	1,428,758		1,832,805
Stockholders' Equity Attributable to Noncontrolling Interest	775,273		349,489
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest	2,204,031		2,182,294
Liabilities and Equity	$ 3,922,914		$ 3,209,331