LOANS AND ALLOWANCE FOR LOAN LOSSES (Impairment Method by Loan Category) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Dec. 31, 2012
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	$ 4,564		$ 3,756
Ending balance: impaired loans collectively evaluated for impairment	10,916		11,675
Ending balance: all other loans collectively evaluated for impairment	59,214		65,602
Balance, end of period	74,694	78,018	81,033	84,277	85,633	91,602
Total loans:
Ending balance: impaired loans individually evaluated for impairment	51,221		57,005
Ending balance: impaired loans collectively evaluated for impairment	104,309		106,578
Ending balance: all other loans collectively evaluated for impairment	2,795,181		2,667,964
Ending balance	2,950,711		2,831,547
Commercial and Industrial [Member]
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	0		0
Ending balance: impaired loans collectively evaluated for impairment	598		497
Ending balance: all other loans collectively evaluated for impairment	13,261		12,904
Balance, end of period	13,859	13,731	13,401	14,024	13,966	13,572
Total loans:
Ending balance: impaired loans individually evaluated for impairment	5,512		3,480
Ending balance: impaired loans collectively evaluated for impairment	6,283		7,043
Ending balance: all other loans collectively evaluated for impairment	634,067		590,181
Ending balance	645,862		600,704
Real Estate Construction and Development [Member]
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	0		62
Ending balance: impaired loans collectively evaluated for impairment	231		232
Ending balance: all other loans collectively evaluated for impairment	2,502		7,113
Balance, end of period	2,733	6,600	7,407	9,002	11,412	14,434
Total loans:
Ending balance: impaired loans individually evaluated for impairment	2,869		3,440
Ending balance: impaired loans collectively evaluated for impairment	1,686		1,474
Ending balance: all other loans collectively evaluated for impairment	71,054		116,748
Ending balance	75,609		121,662
One-to-Four-Family Residential [Member]
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	1,198		2,275
Ending balance: impaired loans collectively evaluated for impairment	8,103		8,937
Ending balance: all other loans collectively evaluated for impairment	19,801		21,407
Balance, end of period	29,102	29,145	32,619	34,713	35,266	38,897
Total loans:
Ending balance: impaired loans individually evaluated for impairment	8,764		12,276
Ending balance: impaired loans collectively evaluated for impairment	91,265		93,301
Ending balance: all other loans collectively evaluated for impairment	897,552		815,911
Ending balance	997,581		921,488
Multi-family residential [Member]
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	1,891		1,034
Ending balance: impaired loans collectively evaluated for impairment	1,297		1,404
Ending balance: all other loans collectively evaluated for impairment	4,569		2,811
Balance, end of period	7,757	7,374	5,249	4,161	4,122	4,252
Total loans:
Ending balance: impaired loans individually evaluated for impairment	24,900		28,641
Ending balance: impaired loans collectively evaluated for impairment	693		1,107
Ending balance: all other loans collectively evaluated for impairment	100,717		91,556
Ending balance	126,310		121,304
Commercial Real Estate [Member]
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	1,475		385
Ending balance: impaired loans collectively evaluated for impairment	687		605
Ending balance: all other loans collectively evaluated for impairment	18,753		21,062
Balance, end of period	20,915	20,820	22,052	22,079	20,573	20,048
Total loans:
Ending balance: impaired loans individually evaluated for impairment	9,176		9,168
Ending balance: impaired loans collectively evaluated for impairment	4,378		3,634
Ending balance: all other loans collectively evaluated for impairment	1,075,876		1,035,432
Ending balance	1,089,430		1,048,234
Consumer and installment and net deferred loan fees [Member]
Allowance for loan losses:
Ending balance: impaired loans individually evaluated for impairment	0		0
Ending balance: impaired loans collectively evaluated for impairment	0		0
Ending balance: all other loans collectively evaluated for impairment	328		305
Balance, end of period	328	348	305	298	294	399
Total loans:
Ending balance: impaired loans individually evaluated for impairment	0		0
Ending balance: impaired loans collectively evaluated for impairment	4		19
Ending balance: all other loans collectively evaluated for impairment	15,915		18,136
Ending balance	$ 15,919		$ 18,155