INTEREST-BEARING DEPOSITS AND SECURITIES (Held-to-maturity Securities) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	$ 133,649	$ 131,258
Gross Unrealized Gains	(6,935)	(6,424)
Gross Unrealized Losses	(85)	(74)
Fair Value	140,499	137,608
Percent of Total Amortized Cost	100.00%		100.00%
U.S. Government and agency obligations [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	2,136	2,146
Gross Unrealized Gains	(2)	0
Gross Unrealized Losses	0	(19)
Fair Value	2,138	2,127
Percent of Total Amortized Cost	1.60%		1.60%
Total municipal bonds [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	122,487	119,951
Gross Unrealized Gains	(6,723)	(6,319)
Gross Unrealized Losses	(82)	(48)
Fair Value	129,128	126,222
Percent of Total Amortized Cost	91.70%		91.40%
Taxable municipal bonds [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	12,771	12,988
Gross Unrealized Gains	(428)	(371)
Gross Unrealized Losses	0	(1)
Fair Value	13,199	13,358
Percent of Total Amortized Cost	9.60%		9.90%
Tax exempt municipal bonds [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	109,716	106,963
Gross Unrealized Gains	(6,295)	(5,948)
Gross Unrealized Losses	(82)	(47)
Fair Value	115,929	112,864
Percent of Total Amortized Cost	82.10%		81.50%
Corporate bonds [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	1,800	1,800
Gross Unrealized Gains	0	0
Gross Unrealized Losses	0	0
Fair Value	1,800	1,800
Percent of Total Amortized Cost	1.30%		1.40%
Total mortgage-backed or related securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	7,226	7,361
Gross Unrealized Gains	(210)	(105)
Gross Unrealized Losses	(3)	(7)
Fair Value	7,433	7,459
Percent of Total Amortized Cost	5.40%	5.60%
1-4 residential agency guaranteed [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	1,477	1,580
Gross Unrealized Gains	(18)	(1)
Gross Unrealized Losses	(3)	(7)
Fair Value	1,492	1,574
Percent of Total Amortized Cost	1.10%	1.20%
Multifamily agency guaranteed [Member]
Schedule of Held-to-maturity Securities [Line Items]
Amortized Cost	5,749	5,781
Gross Unrealized Gains	(192)	(104)
Gross Unrealized Losses	0	0
Fair Value	$ 5,941	$ 5,885
Percent of Total Amortized Cost	4.30%		4.40%