Condensed Financial Information (Parent Company Only) - Condensed Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating Activities
Net income	$ 7,096	$ 6,326	$ 6,121	$ 5,696	$ 3,576	$ 6,288	$ 6,008	$ 6,028	$ 25,239	$ 21,900	$ 15,226
Depreciation and amortization									6,926	5,667	5,299
Share-based compensation expense									1,680	1,596	1,038
Net change in other assets									(42,079)	(11,807)	(2,273)
Net change in other liabilities									5,270	(83)	554
Net cash (used in) provided by operating activities									(43,577)	29,356	24,624
Investing activities
Purchase of premises and equipment									(4,105)	(2,219)	(1,517)
Net cash used in investing activities									(313,273)	(638,713)	(908,151)
Financing activities
Cash dividends paid									(2,418)	(2,230)	(1,675)
Net proceeds from issuance of subordinated debt									35,418	0	0
Repayment of subordinated debt									0	(3,000)	0
Net proceeds from common stock issuance									0	54,334	51,636
Repurchase of common stock									(9,784)	(216)	0
Other, net									(329)	(210)	(173)
Net cash provided by financing activities									495,499	750,088	892,056
Cash and cash equivalents, beginning of year				188,712					188,712
Cash and cash equivalents, end of year	327,361				188,712				327,361	188,712
Parent Company
Operating Activities
Net income									25,239	21,900	15,226
Equity in undistributed net income of subsidiaries									(30,367)	(25,466)	(17,989)
Depreciation and amortization									647	568	572
Share-based compensation expense									288	243	175
Net change in other assets									(508)	1,769	(1,453)
Net change in other liabilities									(87)	79	(326)
Net cash (used in) provided by operating activities									(4,788)	(907)	(3,795)
Investing activities
Capital contribution to the Bank									(25,000)	(35,000)	(42,000)
Purchase of premises and equipment									(13)	0	(148)
Net cash used in investing activities									(25,013)	(35,000)	(42,148)
Financing activities
Cash dividends paid									(2,418)	(2,230)	(1,675)
Net proceeds from issuance of subordinated debt									35,418	0	0
Repayment of subordinated debt									0	(3,000)	0
Principal payment on loan from the Bank									(300)	(300)	(400)
Net proceeds from common stock issuance									0	54,334	51,636
Repurchase of common stock									(9,784)	(216)	0
Other, net									(93)	(210)	(173)
Net cash provided by financing activities									22,823	48,378	49,388
Net increase in cash and cash equivalents									(6,978)	12,471	3,445
Cash and cash equivalents, beginning of year				$ 45,281				$ 32,810	45,281	32,810	29,365
Cash and cash equivalents, end of year	$ 38,303				$ 45,281				$ 38,303	$ 45,281	$ 32,810