LOANS AND ALLOWANCE FOR LOAN LOSSES (Impairment Method by Loan Category) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	$ 3,598	$ 11,738
Ending balance: impaired loans collectively evaluated for impairment	14,354	18,891
Ending balance: all other loans collectively evaluated for impairment	73,650	107,081
Ending balance: Total	91,602	137,710	201,033	266,448
Financing receivables:
Ending balance: impaired loans individually evaluated for impairment	119,483	209,169
Ending balance: impaired loans collectively evaluated for impairment	119,306	137,524
Ending balance: all other loans collectively evaluated for impairment	2,625,825	2,906,475
Ending balance: Total	2,864,614	3,253,168
Commercial and Industrial
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	75	4,276
Ending balance: impaired loans collectively evaluated for impairment	601	1,199
Ending balance: all other loans collectively evaluated for impairment	12,896	21,768
Ending balance: Total	13,572	27,243	28,000
Financing receivables:
Ending balance: impaired loans individually evaluated for impairment	7,884	40,527
Ending balance: impaired loans collectively evaluated for impairment	11,166	19,077
Ending balance: all other loans collectively evaluated for impairment	591,251	665,591
Ending balance: Total	610,301	725,195
Real Estate Construction and Development
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	121	1,752
Ending balance: impaired loans collectively evaluated for impairment	1,331	1,680
Ending balance: all other loans collectively evaluated for impairment	12,982	21,436
Ending balance: Total	14,434	24,868	58,439
Financing receivables:
Ending balance: impaired loans individually evaluated for impairment	39,155	76,475
Ending balance: impaired loans collectively evaluated for impairment	3,028	6,783
Ending balance: all other loans collectively evaluated for impairment	132,796	166,729
Ending balance: Total	174,979	249,987
One-to- Four-Family Residential
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	3,187	3,170
Ending balance: impaired loans collectively evaluated for impairment	10,455	14,338
Ending balance: all other loans collectively evaluated for impairment	25,255	33,356
Ending balance: Total	38,897	50,864	60,762
Financing receivables:
Ending balance: impaired loans individually evaluated for impairment	16,843	16,836
Ending balance: impaired loans collectively evaluated for impairment	98,423	104,201
Ending balance: all other loans collectively evaluated for impairment	871,501	781,401
Ending balance: Total	986,767	902,438
Multi- Family Residential
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	33	110
Ending balance: impaired loans collectively evaluated for impairment	1,105	225
Ending balance: all other loans collectively evaluated for impairment	3,114	4,516
Ending balance: Total	4,252	4,851	5,158
Financing receivables:
Ending balance: impaired loans individually evaluated for impairment	34,636	11,141
Ending balance: impaired loans collectively evaluated for impairment	365	0
Ending balance: all other loans collectively evaluated for impairment	68,683	116,215
Ending balance: Total	103,684	127,356
Commercial Real Estate
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	182	2,430
Ending balance: impaired loans collectively evaluated for impairment	861	1,445
Ending balance: all other loans collectively evaluated for impairment	19,005	25,573
Ending balance: Total	20,048	29,448	47,880
Financing receivables:
Ending balance: impaired loans individually evaluated for impairment	20,965	64,190
Ending balance: impaired loans collectively evaluated for impairment	6,296	7,441
Ending balance: all other loans collectively evaluated for impairment	942,419	1,153,907
Ending balance: Total	969,680	1,225,538
Consumer and Installment
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	0	0
Ending balance: impaired loans collectively evaluated for impairment	1	4
Ending balance: all other loans collectively evaluated for impairment	398	432
Ending balance: Total	399	436	794
Financing receivables:
Ending balance: impaired loans individually evaluated for impairment	0	0
Ending balance: impaired loans collectively evaluated for impairment	28	22
Ending balance: all other loans collectively evaluated for impairment	19,175	22,632
Ending balance: Total	$ 19,203	$ 22,654