LOANS RECEIVABLE AND THE ALLOWANCE FOR LOAN LOSSES (Allowance for Credit Losses) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	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, 2013	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				$ 77,491				$ 82,912					$ 77,491	$ 82,912
Provision for loan losses	0	0	0	0	1,000	3,000	4,000	5,000	5,000	5,000	8,000	17,000	0	13,000	35,000
Recoveries													7,497	7,466
Charge-offs													(9,998)	(25,887)
Ending balance	74,990				77,491				82,912				74,990	77,491	82,912
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	5,188				5,725								5,188	5,725
Allowance collectively evaluated for impairment	69,802				71,766								69,802	71,766
Total allowance for loan losses	74,990				77,491				82,912				74,990	77,491	82,912
Loans individually evaluated for impairment	60,647				63,123								60,647	63,123
Loans collectively evaluated for impairment	3,357,798				3,172,591								3,357,798	3,172,591
Total loans outstanding	3,418,445				3,235,714								3,418,445	3,235,714
Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				15,322				16,457					15,322	16,457
Provision for loan losses													1,639	2,009
Recoveries													2,367	921
Charge-offs													(2,569)	(4,065)
Ending balance	16,759				15,322								16,759	15,322
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	419				1,149								419	1,149
Allowance collectively evaluated for impairment	16,340				14,173								16,340	14,173
Total allowance for loan losses	16,759				15,322								16,759	15,322
Loans individually evaluated for impairment	10,877				11,877								10,877	11,877
Loans collectively evaluated for impairment	1,184,181				1,061,345								1,184,181	1,061,345
Total loans outstanding	1,195,058				1,073,222								1,195,058	1,073,222
Multifamily [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				4,506				3,952					4,506	3,952
Provision for loan losses													800	554
Recoveries													0	0
Charge-offs													0	0
Ending balance	5,306				4,506								5,306	4,506
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	1,139				1,273								1,139	1,273
Allowance collectively evaluated for impairment	4,167				3,233								4,167	3,233
Total allowance for loan losses	5,306				4,506								5,306	4,506
Loans individually evaluated for impairment	5,744				5,000								5,744	5,000
Loans collectively evaluated for impairment	131,409				132,504								131,409	132,504
Total loans outstanding	137,153				137,504								137,153	137,504
Construction and Land [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				14,991				18,184					14,991	18,184
Provision for loan losses													2,195	399
Recoveries													2,275	2,954
Charge-offs													(1,821)	(6,546)
Ending balance	17,640				14,991								17,640	14,991
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	1,762				1,456								1,762	1,456
Allowance collectively evaluated for impairment	15,878				13,535								15,878	13,535
Total allowance for loan losses	17,640				14,991								17,640	14,991
Loans individually evaluated for impairment	12,118				8,613								12,118	8,613
Loans collectively evaluated for impairment	339,140				296,004								339,140	296,004
Total loans outstanding	351,258				304,617								351,258	304,617
Commercial business [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				9,957				15,159					9,957	15,159
Provision for loan losses													1,925	(1,142)
Recoveries													1,673	2,425
Charge-offs													(1,782)	(6,485)
Ending balance	11,773				9,957								11,773	9,957
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	222				133								222	133
Allowance collectively evaluated for impairment	11,551				9,824								11,551	9,824
Total allowance for loan losses	11,773				9,957								11,773	9,957
Loans individually evaluated for impairment	1,298				3,373								1,298	3,373
Loans collectively evaluated for impairment	680,871				614,676								680,871	614,676
Total loans outstanding	682,169				618,049								682,169	618,049
Agricultural Business [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				2,295				1,548					2,295	1,548
Provision for loan losses													97	1,154
Recoveries													697	49
Charge-offs													(248)	(456)
Ending balance	2,841				2,295								2,841	2,295
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	0				0								0	0
Allowance collectively evaluated for impairment	2,841				2,295								2,841	2,295
Total allowance for loan losses	2,841				2,295								2,841	2,295
Loans individually evaluated for impairment	0				0								0	0
Loans collectively evaluated for impairment	228,291				230,031								228,291	230,031
Total loans outstanding	228,291				230,031								228,291	230,031
One- To Four- Family [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				16,475				12,299					16,475	12,299
Provision for loan losses													(2,995)	8,918
Recoveries													145	586
Charge-offs													(2,139)	(5,328)
Ending balance	11,486				16,475								11,486	16,475
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	1,579				1,656								1,579	1,656
Allowance collectively evaluated for impairment	9,907				14,819								9,907	14,819
Total allowance for loan losses	11,486				16,475								11,486	16,475
Loans individually evaluated for impairment	29,834				32,494								29,834	32,494
Loans collectively evaluated for impairment	499,660				549,176								499,660	549,176
Total loans outstanding	529,494				581,670								529,494	581,670
Consumer
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				1,348				1,253					1,348	1,253
Provision for loan losses													1,086	2,571
Recoveries													340	531
Charge-offs													(1,439)	(3,007)
Ending balance	1,335				1,348								1,335	1,348
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	67				58								67	58
Allowance collectively evaluated for impairment	1,268				1,290								1,268	1,290
Total allowance for loan losses	1,335				1,348								1,335	1,348
Loans individually evaluated for impairment	776				1,766								776	1,766
Loans collectively evaluated for impairment	294,246				288,855								294,246	288,855
Total loans outstanding	295,022				290,621								295,022	290,621
Commitments and Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning balance				12,597				14,060					12,597	14,060
Provision for loan losses													(4,747)	(1,463)
Recoveries													0	0
Charge-offs													0	0
Ending balance	7,850				12,597								7,850	12,597
Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]
Allowance individually evaluated for impairment	0				0								0	0
Allowance collectively evaluated for impairment	7,850				12,597								7,850	12,597
Total allowance for loan losses	7,850				12,597								7,850	12,597
Loans individually evaluated for impairment	0				0								0	0
Loans collectively evaluated for impairment	0				0								0	0
Total loans outstanding	$ 0				$ 0								$ 0	$ 0