CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended					9 Months Ended		12 Months Ended
	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 15,342	$ 12,597	$ 17,121	$ 14,536	$ 6,768	$ 41,150	$ 24,072
Adjustments to reconcile net income to net cash from operating activities:
PROVISION FOR LOAN AND LEASE LOSSES	5,931			5,842		16,321	14,913
Impairment loss on assets held for sale						459	256
Depreciation and amortization of premises and equipment						4,701	4,089
Change in fair value of equity securities, net						(1,035)
Net amortization of securities						1,757	2,553
Net gains on sales of securities available-for-sale	(178)					(1,151)	(4)
Losses on disposal of premises and equipment							194
Net gains on sales of assets held for sale						(82)	(1,102)
Net gains on sales of loans	(9,405)			(5,015)		(23,110)	(22,214)
Originations of U.S. government guaranteed loans						(206,418)	(237,945)
Proceeds from U.S. government guaranteed loans sold						209,556	279,390
Accretion of premiums and discounts on acquired loans, net						(17,772)	(14,199)
Net change in servicing assets						(246)	726
Net valuation adjustments on other real estate owned	26			299		189	512
Net gains on sales of other real estate owned	(38)			(489)		(11)	(380)
Other intangible assets amortization expense	2,003			1,898		5,735	3,795
Amortization of time deposit premium						(145)	(273)
Amortization of Federal Home Loan Bank advances premium							(19)
Accretion of junior subordinated debentures discount						439	471
Share-based compensation expense						1,058	1,161
Deferred tax provision, net of valuation						2,364	9,656
Increase in cash surrender value of bank owned life insurance						(253)	(205)
Changes in assets and liabilities:
Accrued interest receivable						(2,920)	(593)
Other assets						(14,310)	(6,720)
Accrued interest payable						1,213	1,095
Accrued expenses and other liabilities						(5,955)	2,937
Net cash provided by operating activities						11,534	62,166
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of securities available-for-sale						(310,950)	(153,995)
Proceeds from maturities and calls of securities available-for-sale						76,297	13,630
Proceeds from paydowns of securities available-for-sale						69,455	45,785
Proceeds from sales of securities available-for-sale						92,103	544
Proceeds from paydowns of securities held-to-maturity							13,778
Purchases of Federal Home Loan Bank stock						(28,170)	(25,293)
Federal Home Loan Bank stock repurchases						23,455	23,794
Net change in loans and leases						(63,565)	(257,598)
Purchases of premises and equipment						(2,291)	(1,380)
Proceeds from sales of assets held for sale						1,373	4,414
Proceeds from sales of other real estate owned						2,539	6,686
Net cash received in acquisition of business						4,306	20,374
Net cash used in investing activities						(135,448)	(309,261)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase in deposits						40,372	275,443
Proceeds from Federal Home Loan Bank advances						6,358,600	4,460,000
Repayments of Federal Home Loan Bank advances						(6,282,900)	(4,396,487)
Proceeds from line of credit						5,680
Repayments of line of credit						(11,335)
Net decrease in securities sold under agreements to repurchase						(1,876)	(6,741)
Dividends paid on preferred stock						(587)	(587)
Proceeds from issuance of common stock upon exercise of stock options						2,359	1,702
Proceeds from issuance of common stock						580	172
Net cash provided by financing activities						110,893	333,502
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS						(13,021)	86,407
CASH AND CASH EQUIVALENTS, beginning of period		$ 121,860	144,756		$ 58,349	121,860	58,349	$ 58,349
CASH AND CASH EQUIVALENTS, end of period	$ 108,839		$ 121,860	$ 144,756		108,839	144,756	$ 121,860
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid during the period for interest						35,021	16,868
Cash payments during the period for taxes						16,090	3,114
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Change in fair value of available-for-sale securities, net of tax						17,041	(10,725)
Change in fair value of cash flow hedges, net of tax						(5,142)	4,213
Delayed payments of mortgage-backed securities						720	229
Transfer of securities from held-to-maturity to available-for-sale						94,837
Reclassification of equity and other securities						6,609
Transfers of loans to other real estate owned						3,916	1,527
Internally financed sale of other real estate owned						183	444
Transfers of land and premises to assets held for sale						2,733	2,531
Transfers of assets held for sale to premises and equipment							(415)
Transfers of premises and equipment to other assets							35
Transfer of other assets to assets held for sale							16
Due from counterparties						47,045	14,334
Due to broker							6,983
Total assets acquired from acquisition						341,375	1,142,766
Total liabilities assumed from acquisition						305,892	1,036,609
Common stock and stock options issued due to acquisition of business						$ 29,320	$ 152,127