LOANS AND ALLOWANCE FOR LOAN LOSSES - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Dec. 31, 2016
Allowance for loan losses:
Balance, beginning of period	$ 21,010	$ 14,917	$ 17,911	$ 13,098
Provision for loan losses	6,908	2,214	11,258	4,569
Charge-offs	(4,207)	(12)	(5,942)	(606)
Recoveries	11	66	495	124
Net charge-offs	(4,196)	54	(5,447)	(482)
Balance, end of period	23,722	17,185	23,722	17,185
Allowance for loan losses related to:
Individually evaluated for impairment					$ 3,829	$ 1,654
Collectively evaluated for impairment					19,893	16,257
Total allowance for loan losses	21,010	14,917	17,911	13,098	23,722	17,911
Recorded investment in loans:
Individually evaluated for impairment					31,115	20,957
Collectively evaluated for impairment					2,170,425	1,870,678
Total loans evaluated for impairment					2,201,540	1,891,635
Commercial and industrial
Allowance for loan losses:
Balance, beginning of period	6,282	4,105	5,059	3,644
Provision for loan losses	3,925	781	6,423	1,640
Charge-offs	(4,059)	(8)	(5,794)	(451)
Recoveries	11	22	471	67
Net charge-offs	(4,048)	14	(5,323)	(384)
Balance, end of period	6,159	4,900	6,159	4,900
Allowance for loan losses related to:
Individually evaluated for impairment					2,947	1,543
Collectively evaluated for impairment					3,212	3,516
Total allowance for loan losses	6,282	4,105	5,059	3,644	6,159	5,059
Recorded investment in loans:
Individually evaluated for impairment					13,030	8,408
Collectively evaluated for impairment					432,999	408,344
Total loans evaluated for impairment					446,029	416,752
Mortgage warehouse
Allowance for loan losses:
Balance, beginning of period	0	0	0	0
Provision for loan losses	0	0	0	0
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Net charge-offs	0	0	0	0
Balance, end of period	0	0	0	0
Allowance for loan losses related to:
Individually evaluated for impairment					0	0
Collectively evaluated for impairment					0	0
Total allowance for loan losses	0	0	0	0	0	0
Recorded investment in loans:
Individually evaluated for impairment					0	0
Collectively evaluated for impairment					83,577	67,038
Total loans evaluated for impairment					83,577	67,038
Commercial real estate (including multi-family residential) | Commercial real estate (including multi-family residential)
Allowance for loan losses:
Balance, beginning of period	9,328	6,846	8,950	5,914
Provision for loan losses	2,580	1,563	2,958	2,624
Charge-offs	0	0	0	(129)
Recoveries	0	43	0	43
Net charge-offs	0	43	0	(86)
Balance, end of period	11,908	8,452	11,908	8,452
Allowance for loan losses related to:
Individually evaluated for impairment					862	105
Collectively evaluated for impairment					11,046	8,845
Total allowance for loan losses	9,328	6,846	8,950	5,914	11,908	8,950
Recorded investment in loans:
Individually evaluated for impairment					16,499	12,321
Collectively evaluated for impairment					1,028,721	879,668
Total loans evaluated for impairment					1,045,220	891,989
Commercial real estate (including multi-family residential) | Commercial real estate construction and land development
Allowance for loan losses:
Balance, beginning of period	1,894	1,368	1,217	1,221
Provision for loan losses	443	(76)	1,110	71
Charge-offs	0	0	0	0
Recoveries	0	0	10	0
Net charge-offs	0	0	10	0
Balance, end of period	2,337	1,292	2,337	1,292
Allowance for loan losses related to:
Individually evaluated for impairment					0	0
Collectively evaluated for impairment					2,337	1,217
Total allowance for loan losses	1,894	1,368	1,217	1,221	2,337	1,217
Recorded investment in loans:
Individually evaluated for impairment					209	0
Collectively evaluated for impairment					225,365	159,247
Total loans evaluated for impairment					225,574	159,247
Commercial real estate (including multi-family residential) | 1-4 family residential (including home equity)
Allowance for loan losses:
Balance, beginning of period	1,988	1,642	1,876	1,432
Provision for loan losses	272	101	374	301
Charge-offs	0	0	0	0
Recoveries	0	0	10	10
Net charge-offs	0	0	10	10
Balance, end of period	2,260	1,743	2,260	1,743
Allowance for loan losses related to:
Individually evaluated for impairment					0	0
Collectively evaluated for impairment					2,260	1,876
Total allowance for loan losses	1,988	1,642	1,876	1,432	2,260	1,876
Recorded investment in loans:
Individually evaluated for impairment					1,327	217
Collectively evaluated for impairment					282,072	246,770
Total loans evaluated for impairment					283,399	246,987
Commercial real estate (including multi-family residential) | Residential construction
Allowance for loan losses:
Balance, beginning of period	835	887	748	820
Provision for loan losses	148	(159)	235	(92)
Charge-offs	0	0	0	0
Recoveries	0	0	0	0
Net charge-offs	0	0	0	0
Balance, end of period	983	728	983	728
Allowance for loan losses related to:
Individually evaluated for impairment					0	0
Collectively evaluated for impairment					983	748
Total allowance for loan losses	835	887	748	820	983	748
Recorded investment in loans:
Individually evaluated for impairment					0	0
Collectively evaluated for impairment					106,299	98,657
Total loans evaluated for impairment					106,299	98,657
Consumer and other
Allowance for loan losses:
Balance, beginning of period	683	69	61	67
Provision for loan losses	(460)	4	158	25
Charge-offs	(148)	(4)	(148)	(26)
Recoveries	0	1	4	4
Net charge-offs	(148)	(3)	(144)	(22)
Balance, end of period	75	70	75	70
Allowance for loan losses related to:
Individually evaluated for impairment					20	6
Collectively evaluated for impairment					55	55
Total allowance for loan losses	$ 683	$ 69	$ 61	$ 67	75	61
Recorded investment in loans:
Individually evaluated for impairment					50	11
Collectively evaluated for impairment					11,392	10,954
Total loans evaluated for impairment					$ 11,442	$ 10,965