CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Preferred Stock Series C Preferred Stock	Common Stock	Additional Paid-in Capital	Retained Earnings	Treasury Stock	Accumulated Other Comprehensive Loss	Unallocated Common Stock Held by ESOP
Balance at beginning of period at Dec. 31, 2012	$ 1,293,989	$ 0	$ 1,665	$ 884,689	$ 1,891,022	$ (1,406,755)	$ (73,090)	$ (3,542)
Increase (Decrease) in Stockholders' Equity
Net income	66,593				66,593
Other comprehensive income (loss), net of tax	34,840						34,840
Issuance of preferred stock	129,796	129,796
Dividends on preferred stock	(7,214)				(7,214)
Dividends on common stock	(15,667)				(15,667)
Restricted stock grants	0			(5,200)	(5,878)	11,078
Forfeitures of restricted stock	0			1,234	1,110	(2,344)
Stock-based compensation	6,969			6,909	60
Net tax benefit excess (shortfall) from stock-based compensation	(800)			(800)
Allocation of ESOP stock	11,007			7,465				3,542
Balance at end of period at Dec. 31, 2013	1,519,513	129,796	1,665	894,297	1,930,026	(1,398,021)	(38,250)	0
Increase (Decrease) in Stockholders' Equity
Net income	95,916				95,916
Other comprehensive income (loss), net of tax	(27,701)						(27,701)
Dividends on preferred stock	(8,775)				(8,775)
Dividends on common stock	(15,868)				(15,868)
Sales of treasury stock	8,121				(4,595)	12,716
Restricted stock grants	0			(6,472)	(4,160)	10,632
Forfeitures of restricted stock	0			374	275	(649)
Stock-based compensation	8,672			8,658	14
Net tax benefit excess (shortfall) from stock-based compensation	192			192
Balance at end of period at Dec. 31, 2014	1,580,070	129,796	1,665	897,049	1,992,833	(1,375,322)	(65,951)	0
Increase (Decrease) in Stockholders' Equity
Net income	88,075				88,075
Other comprehensive income (loss), net of tax	7,334						7,334
Dividends on preferred stock	(8,775)				(8,775)
Dividends on common stock	(16,081)				(16,081)
Sales of treasury stock	6,168				(3,802)	9,970
Common stock repurchased	(6,869)					(6,869)
Restricted stock units vesting	0			(3,378)	(4,189)	7,567
Restricted stock grants	0			(5,608)	(3,273)	8,881
Forfeitures of restricted stock	0			777	586	(1,363)
Stock-based compensation	11,411			11,394	17
Net tax benefit excess (shortfall) from stock-based compensation	2,115			2,115
Balance at end of period at Dec. 31, 2015	$ 1,663,448	$ 129,796	$ 1,665	$ 902,349	$ 2,045,391	$ (1,357,136)	$ (58,617)	$ 0