FAIR VALUE OF FINANCIAL INSTRUMENTS (Assets and Liabilities Measured on a Recurring Basis) (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	$ 25,741	$ 25,896
Securities—available-for-sale	1,561,009	1,636,223
Advances from FHLB	606,000	540,189
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	25,741	25,896
Securities—available-for-sale	1,561,009	1,636,223
Total assets	1,751,590	1,830,847
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	113,621	114,091
Total liabilities	125,768	118,883
Recurring [Member] | Interest rate lock and forward sale commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1,545	3,138
Derivative liabilities	1,080	3,138
Recurring [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	13,604	471
Derivative liabilities	11,067	1,654
Recurring [Member] | U.S. Government and agency obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	125,068	149,112
Recurring [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	110,910	117,822
Recurring [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	4,561	3,495
Recurring [Member] | TPS and TRUP CDOs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	25,741	25,896
Recurring [Member] | Mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	1,312,433	1,343,861
Recurring [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	8,037	21,933
Recurring [Member] | Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	149,691	164,767
Recurring [Member] | Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	0	0
Securities—available-for-sale	0	0
Total assets	0	0
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	0	0
Total liabilities	0	0
Recurring [Member] | Level 1 [Member] | Interest rate lock and forward sale commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Recurring [Member] | Level 1 [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Recurring [Member] | Level 1 [Member] | U.S. Government and agency obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Level 1 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Level 1 [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Level 1 [Member] | TPS and TRUP CDOs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	0	0
Recurring [Member] | Level 1 [Member] | Mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Level 1 [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Level 1 [Member] | Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	0	0
Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	0	0
Securities—available-for-sale	1,561,009	1,636,223
Total assets	1,725,849	1,804,951
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	0	0
Total liabilities	12,147	4,792
Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest rate lock and forward sale commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	1,545	3,138
Derivative liabilities	1,080	3,138
Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	13,604	471
Derivative liabilities	11,067	1,654
Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | U.S. Government and agency obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	125,068	149,112
Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	110,910	117,822
Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	4,561	3,495
Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | TPS and TRUP CDOs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	0	0
Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	1,312,433	1,343,861
Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	8,037	21,933
Recurring [Member] | Fair Value, Inputs, Level 2 [Member] | Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	149,691	164,767
Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	25,741	25,896
Securities—available-for-sale	0	0
Total assets	25,741	25,896
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	113,621	114,091
Total liabilities	113,621	114,091
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate lock and forward sale commitments [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	0	0
Derivative liabilities	0	0
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | U.S. Government and agency obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | TPS and TRUP CDOs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	25,741	25,896
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	0	0
Recurring [Member] | Fair Value, Inputs, Level 3 [Member] | Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	$ 0	$ 0