Basis of Presentation and Significant Accounting Policies - Effects of Adopting Topic 842 (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets
Other current assets	$ 274,259	$ 258,908	$ 274,857
Property, plant and equipment, net	10,898,210	10,732,909	11,026,020
Operating lease right-of-use assets	1,457,822	1,468,762
Intangible assets, net	2,243,106	2,310,091	2,333,296
Other assets	458,097	469,784	533,252
Liabilities
Current portion of operating lease liabilities	132,162	144,405
Current portion of finance lease liabilities	56,024	70,795
Current portion of capital lease and other financing obligations		0	77,844
Other current liabilities	113,969	120,540	126,995
Operating lease liabilities, less current portion	1,316,522	1,312,262
Finance lease liabilities, less current portion	1,166,234	1,165,188
Capital lease and other financing obligations, less current portion		0	1,441,077
Other liabilities	544,062	541,491	629,763
Equity
Retained earnings	$ 1,002,053	883,975	$ 889,948
Topic 842
Assets
Other current assets		(15,949)
Property, plant and equipment, net		(293,111)
Operating lease right-of-use assets		1,468,762
Intangible assets, net		(23,205)
Other assets		(63,468)
Liabilities
Current portion of operating lease liabilities		144,405
Current portion of finance lease liabilities		70,795
Current portion of capital lease and other financing obligations		(77,844)
Other current liabilities		(6,455)
Operating lease liabilities, less current portion		1,312,262
Finance lease liabilities, less current portion		1,165,188
Capital lease and other financing obligations, less current portion		(1,441,077)
Other liabilities		(88,272)
Equity
Retained earnings		$ (5,973)