FAIR VALUE OF FINANCIAL INSTRUMENTS (Assets and Liabilities Measured on a Recurring Basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	$ 23,466	$ 24,568
Securities—available-for-sale	1,339,057	800,917
Advances from FHLB at fair value	263,349	54,216
Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	23,466	24,568
Securities—available-for-sale	1,339,057	800,917
Total assets	1,434,772	843,897
Advances from FHLB at fair value	263,349	54,216
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	97,280	95,200
Total liabilities	367,930	158,035
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	664	8,330
Derivative liabilities	115	8,330
Recurring [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	7,186	482
Derivative liabilities	7,186	289
Recurring [Member] | U.S. Government and agency obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	1,305	1,326
Securities—available-for-sale	87,585	56,978
Recurring [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	331	335
Securities—available-for-sale	114,646	109,853
Recurring [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	10,602	10,283
Recurring [Member] | TPS and TRUP CDOs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	21,675	21,143
Recurring [Member] | Mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading		1,641
Securities—available-for-sale	1,092,432	594,712
Recurring [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	28,207	28,993
Recurring [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	155	123
Securities—available-for-sale	5,585	98
Recurring [Member] | Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Loans Held-for-sale, Fair Value Disclosure	64,399	9,600
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
Advances from FHLB at fair value	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—trading	0	0
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—trading	0	0
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—trading		0
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] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	0	0
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] | Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	1,791	3,425
Securities—available-for-sale	1,339,057	800,917
Total assets	1,413,097	822,754
Advances from FHLB at fair value	263,349	54,216
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	0	0
Total liabilities	270,650	62,835
Recurring [Member] | 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	664	8,330
Derivative liabilities	115	8,330
Recurring [Member] | Level 2 [Member] | Interest rate swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative assets	7,186	482
Derivative liabilities	7,186	289
Recurring [Member] | Level 2 [Member] | U.S. Government and agency obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	1,305	1,326
Securities—available-for-sale	87,585	56,978
Recurring [Member] | Level 2 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	331	335
Securities—available-for-sale	114,646	109,853
Recurring [Member] | Level 2 [Member] | Corporate bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	10,602	10,283
Recurring [Member] | 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] | Level 2 [Member] | Mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading		1,641
Securities—available-for-sale	1,092,432	594,712
Recurring [Member] | Level 2 [Member] | Asset-backed Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—available-for-sale	28,207	28,993
Recurring [Member] | Level 2 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	155	123
Securities—available-for-sale	5,585	98
Recurring [Member] | 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	64,399	9,600
Recurring [Member] | Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	21,675	21,143
Securities—available-for-sale	0	0
Total assets	21,675	21,143
Advances from FHLB at fair value	0	0
Junior subordinated debentures net of unamortized deferred issuance costs at fair value	97,280	95,200
Total liabilities	97,280	95,200
Recurring [Member] | 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] | 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] | Level 3 [Member] | U.S. Government and agency obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	0	0
Securities—available-for-sale	0	0
Recurring [Member] | Level 3 [Member] | Municipal bonds [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	0	0
Securities—available-for-sale	0	0
Recurring [Member] | 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] | Level 3 [Member] | TPS and TRUP CDOs [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	21,675	21,143
Recurring [Member] | Level 3 [Member] | Mortgage-backed securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading		0
Securities—available-for-sale	0	0
Recurring [Member] | 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] | Level 3 [Member] | Equity Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities—trading	0	0
Securities—available-for-sale	0	0
Recurring [Member] | 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