Parent Only Condensed Financial Statements - Condensed Income Statement (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
Income:
Dividend from subsidiary													$ 16
Gain on sale of securities									$ (198)	[1]	$ 2	[1]	500
Expense
Salaries and employee benefits									35,978	[1]	36,133	[1]	31,506
Income before income taxes	$ 12,187	$ 11,806	$ 11,998	$ 11,727	$ 10,901	$ 9,242	$ 10,635	$ 8,806	47,718		39,584		33,179
Income tax benefit	2,902	2,854	3,169	2,832	2,997	2,171	2,643	2,096	11,757		9,907		13,640
Net income	$ 9,285	$ 8,952	$ 8,829	$ 8,895	$ 7,904	$ 7,071	$ 7,992	$ 6,710	35,961		29,677		19,539
Parent [Member]
Income:
Dividend from subsidiary									17,200		7,750		15,500
Gain on sale of securities									0		0		918
Other operating income									0		0		16
Total income									17,200		7,750		16,434
Expense
Salaries and employee benefits									582		516		481
Other expenses									2,664		2,533		2,276
Total expenses									3,246		3,049		2,757
Income before income taxes									13,954		4,701		13,677
Income tax benefit									(1,138)		(1,150)		(1,602)
Income before equity in undistributed income of subsidiary									15,092		5,851		15,279
Equity in undistributed income of subsidiary									20,869		23,826		4,260
Net income									$ 35,961		$ 29,677		$ 19,539

[1] Not within the scope of ASC 606. Revenue streams are not related to contracts with customers and are accounted for on an accrual basis under other provisions of GAAP.