Condensed Consolidated Statements of Changes in Shareholders' Equity (Unaudited) (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss), net [Member]	Treasury Stock [Member]	Unearned ESOP Shares [Member]
Beginning balance at Dec. 31, 2011	$ 758,543	$ 105,563	$ 365,868	$ 294,056	$ 2,001	$ (7,345)	$ (1,600)
Beginning balance, shares at Dec. 31, 2011		104,916,994
Net Income	23,372			23,372
Other comprehensive income (loss)	833				833
ESOP market value adjustment ($477, net of $167 tax benefit)	(310)		(310)
Discount on dividend reinvestment plan purchases	(42)		(42)
Tax benefit of stock options exercised	1		1
Treasury stock acquired	(3,045)					(3,045)
Treasury stock acquired, shares		(469,700)
Treasury stock reissued	354			(296)		650
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		224,000
Treasury stock reissued, shares		57,552
Restricted stock	186		24	(1,264)		1,426
Dividends, Common Stock, Cash	8,402			8,402
Amortization of ESOP Award	1,000						1,000
Ending balance at Jun. 30, 2012	772,490	105,563	365,541	307,466	2,834	(8,314)	(600)
Ending balance, shares at Jun. 30, 2012		104,728,846
Beginning balance at Dec. 31, 2012	746,007	105,563	365,354	315,608	1,259	(41,777)	0
Beginning balance, shares at Dec. 31, 2012	99,629,494	99,629,494
Net Income	16,369			16,369
Other comprehensive income (loss)	(17,981)				(17,981)
Discount on dividend reinvestment plan purchases	(55)		(55)
Tax benefit of stock options exercised	0
Treasury stock acquired	(23,247)					(23,247)
Treasury stock acquired, shares		(3,267,692)
Treasury stock reissued	176			0		176
Stock Issued During Period, Shares, Restricted Stock Award, Net of Forfeitures		55,000
Treasury stock reissued, shares		25,359
Restricted stock	248		53	0		195
Dividends, Common Stock, Cash	10,842			10,842
Ending balance at Jun. 30, 2013	$ 710,675	$ 105,563	$ 365,352	$ 321,135	$ (16,722)	$ (64,653)	$ 0
Ending balance, shares at Jun. 30, 2013	96,442,161	96,442,161