Derivative Financial Instruments - Impact of Derivatives on Consolidated Statement of Changes in Stockholders' Equity (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Amount of gain recognized in other comprehensive income (loss)	$ (12,821)	$ 18,728
Less: amount of loss reclassified in interest expense	1,296	(1,562)
Total change in other comprehensive income (loss) for unrealized gains (losses) on derivatives, before income tax (expense) benefit	(14,117)	$ 20,290
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	$ 3,700