OFF BALANCE SHEET RISKS, COMMITMENTS AND CONTINGENT LIABILITIES (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Commitments and letters of credit
Loan commitment, line credit	$ 1,687,652	$ 1,373,917
Unused warehouse lines of credit
Commitments and letters of credit
Loan commitment, line credit	518,840	453,110
Unused home equity lines of credit
Commitments and letters of credit
Loan commitment, line credit	364,319	341,434
Unused loan commitments - other
Commitments and letters of credit
Loan commitment, line credit	792,405	560,629
Commitments to purchase loans
Commitments and letters of credit
Loan commitment, line credit	893	3,176
Standby letters of credit
Commitments and letters of credit
Loan commitment, line credit	$ 11,195	$ 15,568