DEPOSITS (Deposit Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Deposit Liabilities [Line Items]
Non-interest-bearing checking	$ 981,240	$ 777,563
Non-interest-bearing accounts, percent of total	27.60%	22.40%
Interest-bearing checking	410,316	362,542
Interest-bearing checking, percent of total	11.50%	10.40%
Regular savings accounts	727,957	669,596
Regular savings accounts, percent of total	20.50%	19.30%
Money market accounts	408,998	415,456
Money market accounts, percent of total	11.50%	11.90%
Total transaction and saving accounts	2,528,511	2,225,157
Total transaction and saving accounts, percent of total	71.10%	64.00%
Certificates of deposit:
Total certificates of deposit	1,029,293	1,250,497
Total certificate accounts, percent of total	28.90%	36.00%
Total deposits	3,557,804	3,475,654	3,591,198	3,865,550
Total deposits, percent of total	100.00%	100.00%
Included in total deposits:
Public transaction accounts	79,955	72,064
Public fund transaction accounts, percent of total	2.20%	2.10%
Public interest-bearing certificates	60,518	67,112
Public fund interest-bearing certificates, percent of total	1.70%	1.90%
Total public deposits	140,473	139,176
Total public deposits, percent of total	3.90%	4.00%
Total brokered deposits	15,702	49,194
Total brokered deposits, percent of total	0.40%	1.40%
Up to 1.00% [Member]
Certificates of deposit:
Total certificates of deposit	792,674	701,593
Total certificate accounts, percent of total	22.30%	20.20%
Included in total deposits:
Certificates of deposit, interest rate, upper range limit	1.00%
1.01% to 2.00% [Member]
Certificates of deposit:
Total certificates of deposit	155,144	394,285
Total certificate accounts, percent of total	4.30%	11.30%
Included in total deposits:
Certificates of deposit, interest rate, lower range limit	1.01%
Certificates of deposit, interest rate, upper range limit	2.00%
2.01% to 3.00% [Member]
Certificates of deposit:
Total certificates of deposit	59,094	96,334
Total certificate accounts, percent of total	1.60%	2.80%
Included in total deposits:
Certificates of deposit, interest rate, lower range limit	2.01%
Certificates of deposit, interest rate, upper range limit	3.00%
3.01% to 4.00% [Member]
Certificates of deposit:
Total certificates of deposit	12,881	19,495
Total certificate accounts, percent of total	0.40%	0.60%
Included in total deposits:
Certificates of deposit, interest rate, lower range limit	3.01%
Certificates of deposit, interest rate, upper range limit	4.00%
4.01% and greater [Member]
Certificates of deposit:
Total certificates of deposit	$ 9,500	$ 38,790
Total certificate accounts, percent of total	0.30%	1.10%
Included in total deposits:
Certificates of deposit, interest rate, lower range limit	4.01%