OFF BALANCE SHEET RISKS, COMMITMENTS AND CONTINGENT LIABILITIES (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Commitments and letters of credit
Loan commitment, line credit	$ 1,377,567	$ 1,709,869
Unused warehouse lines of credit
Commitments and letters of credit
Loan commitment, line credit	177,912	591,305
Unused home equity lines of credit
Commitments and letters of credit
Loan commitment, line credit	379,836	377,277
Unused loan commitments - other
Commitments and letters of credit
Loan commitment, line credit	805,284	720,645
Standby letters of credit
Commitments and letters of credit
Loan commitment, line credit	12,050	10,642
FHLB letters of credit
Commitments and letters of credit
Loan commitment, line credit	$ 2,485	$ 10,000