Basis of Presentation and Accounting Policies - Cumulative Effect of applying ASC 842 to the Condensed Consolidated Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets	$ 130,009	$ 137,889	$ 140,819
Property and equipment, net	742,559	758,085	812,005
Deferred tax assets	1,467,518	1,510,908	1,499,672
Operating lease assets	60,573	61,674
Total assets	6,543,114	6,261,958	6,245,898
Capital lease obligations, current portion			9,817
Other current liabilities		74,893	40,589
Capital lease obligations, excluding current portion			19,658
Construction financing lease obligation, excluding current portion			561,892
Long-term finance lease liabilities	560,381	569,487
Long-term operating lease liabilities	63,484	64,849
Other long-term liabilities	5,997	5,377	26,280
Accumulated deficit	(2,761,157)	(3,029,788)	(2,989,478)
Total liabilities and shareholders’ equity	$ 6,543,114	6,261,958	6,245,898
Accounting Standards Update 2016-02
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Prepaid expenses and other current assets			(2,930)
Property and equipment, net			(53,920)
Deferred tax assets			11,236
Operating lease assets		$ 61,700	61,674
Total assets			16,060
Capital lease obligations, current portion			(9,817)
Other current liabilities			34,304
Capital lease obligations, excluding current portion			(19,658)
Construction financing lease obligation, excluding current portion			(561,892)
Long-term finance lease liabilities			569,487
Long-term operating lease liabilities			64,849
Other long-term liabilities			(20,903)
Accumulated deficit			(40,310)
Total liabilities and shareholders’ equity			$ 16,060