NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES
Net interest income	$ 35,225	$ 31,038	$ 101,423	$ 75,385
Provision for loan losses	2,500	2,200	6,750	5,300
Net interest income after provision for loan losses	$ 32,725	$ 28,838	$ 94,673	$ 70,085