FAIR VALUE, Carrying Amounts and Estimated Fair Values of Other Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Carrying Value [Member]
Financial assets [Abstract]
Net loans	$ 4,893,832	$ 4,755,974
Financial liabilities [Abstract]
Deposits	7,077,419	6,873,474
Borrowings	133,900	301,300
Subordinated debt held by unconsolidated subsidiary trusts	102,164	102,146
Fair Value [Member]
Financial assets [Abstract]
Net loans	4,958,819	4,808,856
Financial liabilities [Abstract]
Deposits	7,074,685	6,871,098
Borrowings	133,900	301,300
Subordinated debt held by unconsolidated subsidiary trusts	$ 82,380	$ 84,680