CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (USD $) In Thousands, unless otherwise specified	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss, Net of Deferred Taxes [Member]	Unallocated Common Stock of ESOP [Member]	Unearned Restricted Stock Award Common Stock [Member]	Common Stock Held by BMP [Member]	Treasury Stock [Member]
Balance at Dec. 31, 2009		$ 511	$ 214,654	$ 306,787	$ (5,082)	$ (3,701)	$ (2,505)	$ (8,007)	$ (207,884)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised		1	1,011
(Tax Cost) Excess tax benefit of stock benefit plans			112
BMP award distribution			(28)					28
BMP reclassification			8,007	132
Amortization of excess fair value over cost - ESOP stock and stock options expense			1,688
Release from treasury stock for restricted stock award and BMP award shares, net of return of shares to treasury for forfeited shares (150,173 shares, 169,376 shares and 109,824 shares during the years ended December 31, 2012, 2011, and 2010, respectively)			141				(1,479)	0	1,338
Net income for the period	41,389			41,389
Cash dividends declared and paid				(18,640)
Amortization and reversal of net unrealized loss on securities transferred from available-for-sale to held-to-maturity, net of tax					101
Reduction in non credit component of OTTI charge, net of taxes					1,374
(Increase) Decrease in unrealized loss on available-for-sale securities during the period, net of deferred benefit (taxes)					(1,042)
Unrecognized (loss) gain of pension and other postretirement obligations, net of deferred benefit (tax)					(1,547)
Non-credit component of OTTI charge recognized during the period, net of tax					(156)
Amortization of earned portion of ESOP stock						231
Amortization of earned portion of restricted stock awards							1,300
Balance at Dec. 31, 2010	328,734	512	225,585	329,668	(6,352)	(3,470)	(2,684)	(7,979)	(206,546)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised		4	3,665
(Tax Cost) Excess tax benefit of stock benefit plans			431
BMP award distribution			0					0
BMP reclassification			0	0
Amortization of excess fair value over cost - ESOP stock and stock options expense			1,337
Release from treasury stock for restricted stock award and BMP award shares, net of return of shares to treasury for forfeited shares (150,173 shares, 169,376 shares and 109,824 shares during the years ended December 31, 2012, 2011, and 2010, respectively)			503				(1,931)	(676)	2,104
Net income for the period	47,309			47,309
Cash dividends declared and paid				(18,898)
Amortization and reversal of net unrealized loss on securities transferred from available-for-sale to held-to-maturity, net of tax					245
Reduction in non credit component of OTTI charge, net of taxes					714
(Increase) Decrease in unrealized loss on available-for-sale securities during the period, net of deferred benefit (taxes)					(738)
Unrecognized (loss) gain of pension and other postretirement obligations, net of deferred benefit (tax)					(3,564)
Non-credit component of OTTI charge recognized during the period, net of tax					(14)
Amortization of earned portion of ESOP stock						231
Amortization of earned portion of restricted stock awards							1,578
Balance at Dec. 31, 2011	361,034	516	231,521	358,079	(9,709)	(3,239)	(3,037)	(8,655)	(204,442)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Stock options exercised		4	5,604
(Tax Cost) Excess tax benefit of stock benefit plans			389
BMP award distribution			0					0
BMP reclassification			0	0
Amortization of excess fair value over cost - ESOP stock and stock options expense			1,168
Release from treasury stock for restricted stock award and BMP award shares, net of return of shares to treasury for forfeited shares (150,173 shares, 169,376 shares and 109,824 shares during the years ended December 31, 2012, 2011, and 2010, respectively)			359				(1,927)	(145)	1,858
Net income for the period	40,308			40,308
Cash dividends declared and paid				(19,221)
Amortization and reversal of net unrealized loss on securities transferred from available-for-sale to held-to-maturity, net of tax	(111)				111
Reduction in non credit component of OTTI charge, net of taxes					165
(Increase) Decrease in unrealized loss on available-for-sale securities during the period, net of deferred benefit (taxes)	1,900				(1,900)
Unrecognized (loss) gain of pension and other postretirement obligations, net of deferred benefit (tax)	(1,696)				1,696
Non-credit component of OTTI charge recognized during the period, net of tax					(3)
Amortization of earned portion of ESOP stock						232
Amortization of earned portion of restricted stock awards							1,842
Balance at Dec. 31, 2012	$ 391,574	$ 520	$ 239,041	$ 379,166	$ (9,640)	$ (3,007)	$ (3,122)	$ (8,800)	$ (202,584)