Summary of Significant Accounting Policies - EPS and New Accounting Principle (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Earnings per share
Weighted Average Number of Shares Outstanding, Basic	274,122,567	262,053,868	262,049,659
Weighted Average Number of Shares Outstanding, Diluted	274,143,341	262,068,106	262,049,659
New Accounting Pronouncement or Change in Accounting Principle, Retrospective Adjustments [Abstract]
Net deferred income tax liability - long-term	$ 1,370,686	$ 794,796
Deferred Income Tax Liabilities, Net		794,796
As Previously Reported
New Accounting Pronouncement or Change in Accounting Principle, Retrospective Adjustments [Abstract]
Net deferred income tax liability - current		260,373
Net deferred income tax liability - long-term		534,423
Deferred Income Tax Liabilities, Net		794,796
Adjustment Effect
New Accounting Pronouncement or Change in Accounting Principle, Retrospective Adjustments [Abstract]
Net deferred income tax liability - current		(260,373)
Net deferred income tax liability - long-term		$ 260,373
Restricted Stock and Restricted Stock Unit
Earnings per share
Dilutive effect of equity awards	20,774	14,238
Weighted Average Anti-dilutive Awards	2,264,394	1,444,023
Stock options
Earnings per share
Weighted Average Anti-dilutive Awards	553,297	72,592