CASH AND SECURITIES (Schedule of Investments) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Schedule of Investments [Line Items]
Interest-bearing deposits included in cash and due from banks	$ 114,928	$ 69,758
Interest-bearing deposits and marketable securities	782,237	729,089
U.S. Government and agency obligations [Member]
Schedule of Investments [Line Items]
Marketable securities	98,617	341,606
Total securities [Member]
Schedule of Investments [Line Items]
Marketable securities	630,604	621,960
Total municipal bonds [Member]
Schedule of Investments [Line Items]
Marketable securities	135,025	107,460
Taxable municipal bonds [Member]
Schedule of Investments [Line Items]
Marketable securities	31,480	18,497
Tax exempt municipal bonds [Member]
Schedule of Investments [Line Items]
Marketable securities	103,545	88,963
Corporate bonds [Member]
Schedule of Investments [Line Items]
Marketable securities	48,519	42,565
Total Mortgage-backed or related securities [Member]
Schedule of Investments [Line Items]
Marketable securities	305,864	129,927
1-4 residential agency guaranteed [Member]
Schedule of Investments [Line Items]
Marketable securities	115,966	107,173
1-4 residential other [Member]
Schedule of Investments [Line Items]
Marketable securities	1,299	1,835
Multifamily agency guaranteed [Member]
Schedule of Investments [Line Items]
Marketable securities	177,940	20,919
Multifamily other [Member]
Schedule of Investments [Line Items]
Marketable securities	10,659	0
Asset-backed securities [Member]
Schedule of Investments [Line Items]
Marketable securities	42,516	0
Equity securities (excludes FHLB stock) [Member]
Schedule of Investments [Line Items]
Marketable securities	63	402
FHLB stock [Member]
Schedule of Investments [Line Items]
Marketable securities	$ 36,705	$ 37,371