INTEREST-BEARING DEPOSITS AND SECURITIES (Schedule of Investments) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012	Mar. 31, 2012
Open Option Contracts Written [Line Items]
Interest-bearing deposits included in cash and due from banks	$ 96,300	$ 114,928	$ 143,885
Interest-bearing deposits and marketable securities	765,525	782,237	722,531
Total securities [Member]
Open Option Contracts Written [Line Items]
Marketable securities	632,852	630,604	541,275
U.S. Government and agency obligations [Member]
Open Option Contracts Written [Line Items]
Marketable securities	79,959	98,617	238,866
Total municipal bonds [Member]
Open Option Contracts Written [Line Items]
Marketable securities	153,983	135,025	109,036
Taxable municipal bonds [Member]
Open Option Contracts Written [Line Items]
Marketable securities	43,921	31,480	18,071
Tax exempt municipal bonds [Member]
Open Option Contracts Written [Line Items]
Marketable securities	110,062	103,545	90,965
Corporate bonds [Member]
Open Option Contracts Written [Line Items]
Marketable securities	47,233	48,519	43,674
Total mortgage-backed or related securities [Member]
Open Option Contracts Written [Line Items]
Marketable securities	301,117	305,864	149,292
1-4 residential agency guaranteed [Member]
Open Option Contracts Written [Line Items]
Marketable securities	89,036	105,770	112,328
1-4 residential other [Member]
Open Option Contracts Written [Line Items]
Marketable securities	1,282	1,299	1,808
Multifamily agency guaranteed [Member]
Open Option Contracts Written [Line Items]
Marketable securities	200,012	188,136	35,156
Multifamily other [Member]
Open Option Contracts Written [Line Items]
Marketable securities	10,787	10,659	0
Asset-backed Securities [Member]
Open Option Contracts Written [Line Items]
Marketable securities	50,500	42,516	0
SLMA [Member]
Open Option Contracts Written [Line Items]
Marketable securities	32,239	32,474	0
Other asset-backed securities [Member]
Open Option Contracts Written [Line Items]
Marketable securities	18,261	10,042	0
Equity securities (excludes FHLB stock) [Member]
Open Option Contracts Written [Line Items]
Marketable securities	60	63	407
FHLB stock [Member]
Open Option Contracts Written [Line Items]
Marketable securities	$ 36,373	$ 36,705	$ 37,371