Derivative Financial Instruments - Impact of Derivatives on the Statements of Changes in Stockholder's Equity (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Amount of loss recognized in other comprehensive income (loss)	$ (3,901)	$ (26,699)	$ (28,842)
Amount of loss reclassified in interest expense	(17,665)	(21,475)	(9,070)
Total change in other comprehensive income (loss) for unrealized gains (losses) on derivatives, before income tax (expense) benefit	$ 13,764	$ (5,224)	$ (19,772)