Summary of Significant Accounting Policies - Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounting Policies [Abstract]
Income tax (benefit), net of refunds	$ 9,956	$ 6,550	$ (102,154)
Interest, net of amounts capitalized	184,462	170,209	177,074
Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]
Accrued capital expenditures	114,855	83,798	44,712
Dividends declared but not paid	$ 72,926	$ 69,363	$ 65,790