GAINS FROM MORTGAGE BANKING ACTIVITIES (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
GAINS FROM MORTGAGE BANKING ACTIVITIES
Contractual loan origination related fees, net	$ 22,260,000	$ 10,279,000
Fair value of expected future cash flows from servicing recognized at commitment	21,871,000	10,083,000
Fair value of expected guaranty obligation	(1,200,000)	(560,000)
Total gains from mortgage banking activities	42,931,000	19,802,000
Co-broker fees from mortgage banking activities	$ 3,300,000	$ 3,500,000