CONDENSED HOLDING COMPANY ONLY FINANCIAL STATEMENTS (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended									12 Months Ended
	Dec. 31, 2012		Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
ASSETS:
Cash and due from banks	$ 79,076					$ 43,309				$ 79,076	$ 43,309
Investment securities available-for-sale	32,950					174,868				32,950	174,868
Trading securities	4,874					1,774				4,874	1,774
MBS available-for-sale	49,021					93,877				49,021	93,877
Other assets	116,566					118,484				116,566	118,484
Total assets	3,905,399					4,021,180				3,905,399	4,021,180
LIABILITIES AND STOCKHOLDERS' EQUITY:
Trust Preferred securities payable	70,680					70,680				70,680	70,680
Other liabilities	38,463					39,178				38,463	39,178
Stockholders' equity	391,574					361,034				391,574	361,034	328,734
Total liabilities and stockholders' equity	3,905,399					4,021,180				3,905,399	4,021,180
CONDENSED STATEMENTS OF OPERATIONS [Abstract]
Net interest loss	8,551	[1]	33,398	34,498	33,394	34,127	34,172	36,160	35,043	109,842	139,502	135,381
Non-interest (loss) income	16,498	[1]	2,574	2,988	1,790	2,136	2,149	1,734	1,910	23,849	7,929	8,055
Non-interest expense	14,717		15,771	15,676	16,408	14,781	14,964	15,083	16,860	62,572	61,688	61,977
Income tax credit	3,534		8,280	8,004	7,072	7,214	7,976	8,811	7,587	26,890	31,588	28,861
Net income	6,735		11,795	11,531	10,247	12,727	11,164	12,338	11,080	40,308	47,309	41,389
CONDENSED STATEMENTS OF CASH FLOWS [Abstract]
Net income	6,735		11,795	11,531	10,247	12,727	11,164	12,338	11,080	40,308	47,309	41,389
Adjustments to reconcile net income to net cash provided by operating activities:
Credit component of OTTI										181	727	2,475
Net gain on the transfer of securities into trading										0	0	242
Net amortization										2,880	2,935	2,444
(Increase) Decrease in other assets										(6,009)	(5,671)	(5,246)
Increase (Decrease) in other liabilities										3,663	(3,552)	2,245
Net cash provided by operating activities										72,705	62,587	68,181
Cash flows from Investing Activities:
Proceeds from sale of investment securities available-for-sale										22,415	236	2,519
Purchases of investment securities available-for-sale										80,153	293,157	147,426
Net purchases of trading securities										3,158	454	24
Principal collected on MBS available-for-sale										42,822	48,911	78,389
Net cash provided by investing activities										149,568	(39,898)	(60,301)
Cash flows from Financing Activities:
Proceeds disbursed for the repayment of subordinated note										0	0	25,000
Proceeds disbursed for the re-acquisition of trust preferred securities payable										(145)	0	0
Net cash used in financing activities										(187,457)	(69,158)	39,726
Net increase (decrease) in cash and due from banks										34,816	(46,469)	47,606
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD					44,260				90,729	44,260	90,729	43,123
CASH AND CASH EQUIVALENTS, END OF PERIOD	79,076					44,260				79,076	44,260	90,729
Holding Company [Member]
ASSETS:
Cash and due from banks	17,684					10,454				17,684	10,454
Investment securities available-for-sale	3,006					4,559				3,006	4,559
Trading securities	4,874					1,774				4,874	1,774
MBS available-for-sale	716					788				716	788
ESOP loan to subsidiary	3,567					3,721				3,567	3,721
Investment in subsidiaries	429,533					406,045				429,533	406,045
Other assets	3,664					5,530				3,664	5,530
Total assets	463,044					432,871				463,044	432,871
LIABILITIES AND STOCKHOLDERS' EQUITY:
Trust Preferred securities payable	70,680					70,680				70,680	70,680
Other liabilities	790					1,157				790	1,157
Stockholders' equity	391,574					361,034				391,574	361,034
Total liabilities and stockholders' equity	463,044					432,871				463,044	432,871
CONDENSED STATEMENTS OF OPERATIONS [Abstract]
Net interest loss										(4,830)	(4,831)	(5,651)
Dividends received from Bank										20,000	20,000	24,000
Non-interest (loss) income										1,493	453	1,388
Non-interest expense										(635)	(516)	(411)
Income before income taxes and equity in undistributed earnings of direct subsidiaries										16,028	15,106	19,326
Income tax credit										1,823	2,277	1,826
Income before equity in undistributed earnings of direct subsidiaries										17,851	17,383	21,152
Equity in (overdistributed) undistributed earnings of subsidiaries										22,457	29,926	20,237
Net income										40,308	47,309	41,389
CONDENSED STATEMENTS OF CASH FLOWS [Abstract]
Net income										40,308	47,309	41,389
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in (undistributed) overdistributed earnings of direct subsidiaries										(22,457)	(29,926)	(20,237)
Net gain on the sale of investment securities available for sale										(941)	(22)	(609)
Net gain on the transfer of securities into trading										0	0	(242)
Net loss (gain) on trading securities										(103)	34	(75)
Net amortization										0	0	(66)
(Increase) Decrease in other assets										1,866	(296)	694
Increase (Decrease) in other liabilities										(149)	71	(268)
Net cash provided by operating activities										18,524	17,170	20,586
Cash flows from Investing Activities:
Proceeds from sale of investment securities available-for-sale										2,418	226	2,527
Purchases of investment securities available-for-sale										(403)	(291)	(1,433)
Reimbursement from subsidiary for purchases of investment securities available-for-sale										3,062	275	0
Net purchases of trading securities										(2,997)	(318)	(24)
Principal collected on MBS available-for-sale										72	70	85
Principal repayments on ESOP loan										154	142	132
Net cash provided by investing activities										2,306	104	1,287
Cash flows from Financing Activities:
Common stock issued for exercise of stock options										5,608	3,669	1,012
Cash dividends paid to stockholders										(19,208)	(18,887)	(18,628)
Proceeds disbursed for the repayment of subordinated note										0	0	(25,000)
Proceeds disbursed for the re-acquisition of trust preferred securities payable										0	0	0
Net cash used in financing activities										(13,600)	(15,218)	(42,616)
Net increase (decrease) in cash and due from banks										7,230	2,056	(20,743)
CASH AND CASH EQUIVALENTS, BEGINNING OF PERIOD					10,454				8,398	10,454	8,398	29,141
CASH AND CASH EQUIVALENTS, END OF PERIOD	$ 17,684					$ 10,454				$ 17,684	$ 10,454	$ 8,398

[1] (1) During the three months ended December 31, 2012, a charge of $25,582 on the prepayment of REPOS was recognized as a reduction to net interest income, and a gain on the sale of premises and fixed assets of $13,726 was recognized as a component of non-interest income.