Condensed Consolidated Statements of Shareholder's Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Surplus	Accumulated Deficit	Accumulated Other Comprehensive Loss	Non-Controlling Interests
Balance, beginning of period at Dec. 31, 2015	$ 12,624,709	$ 229,475	$ 2,230	$ 15,160,267	$ (2,696,953)	$ (99,336)	$ 29,026
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	39,267				38,739		528
Other comprehensive income, net of tax	67,391					67,391
Preferred stock dividends	(3,219)			(3,219)
Vesting of restricted stock	(6,175)			(6,175)
Restricted stock tax benefit	1,204			1,204
Balance, end of period at Mar. 31, 2016	12,723,177	229,475	2,230	15,152,077	(2,658,214)	(31,945)	29,554
Balance, beginning of period at Dec. 31, 2016	12,750,707	229,475	2,230	14,985,673	(2,327,440)	(168,252)	29,021
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	120,823				120,380		443
Other comprehensive income, net of tax	17,471					17,471
Preferred stock dividends	(3,548)			(3,548)
Capital contribution	46						46
Balance, end of period at Mar. 31, 2017	$ 12,885,499	$ 229,475	$ 2,230	$ 14,982,125	$ (2,207,060)	$ (150,781)	$ 29,510