DEPOSITS AND CUSTOMER REPURCHASE AGREEMENTS (Deposit Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Banking and Thrift [Abstract]
Non-interest-bearing accounts	$ 958,674	$ 981,240	$ 804,562
Interest-bearing checking	399,302	410,316	379,742
Regular savings accounts	751,475	727,957	664,736
Money market accounts	406,736	408,998	405,412
Total transaction and saving accounts	2,516,187	2,528,511	2,254,452
Certificates, within 1 year	694,212	759,626	903,923
Certificates, after 1 year, but within 3 years	196,762	209,790	198,015
Certificates, after 3 years	53,163	59,877	69,359
Total certificate accounts	944,137	1,029,293	1,171,297
Total deposits	3,460,324	3,557,804	3,425,749
Public fund transaction accounts	78,589	79,955	73,507
Public fund interest-bearing certificates	51,759	60,518	62,743
Total public deposits	130,348	140,473	136,250
Total brokered deposits	$ 7,152	$ 15,702	$ 23,521
Non-interest-bearing accounts, percent of total	27.70%	27.60%	23.50%
Interest-bearing checking, percent of total	11.50%	11.50%	11.10%
Regular savings accounts, percent of total	21.70%	20.50%	19.40%
Money market accounts, percent of total	11.80%	11.50%	11.80%
Total transaction and saving accounts, percent of total	72.70%	71.10%	65.80%
Certificates, within 1 year, percent of total	20.10%	21.30%	26.40%
Certificates, after 1 year, but within 3 years, percent of total	5.70%	5.90%	5.80%
Certificates, after 3 years, percent of total	1.50%	1.70%	2.00%
Total certificate accounts, percent of total	27.30%	28.90%	34.20%
Total deposits, percent of total	100.00%	100.00%	100.00%
Public fund transaction accounts, percent of total	2.30%	2.20%	2.20%
Public fund interest-bearing certificates, percent of total	1.50%	1.70%	1.80%
Total public deposits, percent of total	3.80%	3.90%	4.00%
Total brokered deposits, percent of total	0.20%	0.40%	0.70%