Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Statement Of Income And Comprehensive Income [Abstract]
Net loss	$ (71,165)	$ (34,535)
Other comprehensive income (loss):
Net unrealized gains on securities available for sale	31,887	74,546
Net unrealized gains on derivative instruments	2,793	14,167
Other comprehensive income	34,680	88,713
Comprehensive income (loss)	(36,485)	54,178
Dividends on preferred stock	5,480	5,481
Comprehensive income (loss) available to common shareholders	$ (41,965)	$ 48,697