Consolidated Statement of Changes in Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss
Balance at beginning of period at Dec. 31, 2015	$ 1,663,448	$ 129,796	$ 1,665	$ 902,349	$ 2,045,391	$ (1,357,136)	$ (58,617)
Increase (Decrease) in Stockholders' Equity
Net income	18,565				18,565
Other comprehensive (loss) income, net of tax	4,410						4,410
Dividends on preferred stock	(2,194)				(2,194)
Dividends on common stock	(4,053)				(4,053)
Sales of treasury stock	41				(15)	56
Restricted stock grants	0			(10,329)	(3,823)	14,152
Forfeitures of restricted stock	0			45	25	(70)
Stock-based compensation	1,581			1,580	1
Net tax benefit excess from stock-based compensation	3			3
Balance at end of period at Mar. 31, 2016	1,681,801	129,796	1,665	893,648	2,053,897	(1,342,998)	(54,207)
Balance at beginning of period at Dec. 31, 2016	1,714,073	129,796	1,665	830,417	2,155,785	(1,346,709)	(56,881)
Increase (Decrease) in Stockholders' Equity
Net income	14,407				14,407
Other comprehensive (loss) income, net of tax	(32)						(32)
Dividends on preferred stock	(2,194)				(2,194)
Dividends on common stock	(4,049)				(4,049)
Sales of treasury stock	34				(4)	38
Restricted stock grants	0			(10,329)	(434)	10,763
Forfeitures of restricted stock	0			43	17	(60)
Stock-based compensation	1,725			1,725
Balance at end of period at Mar. 31, 2017	$ 1,723,964	$ 129,796	$ 1,665	$ 821,856	$ 2,163,528	$ (1,335,968)	$ (56,913)