Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Comprehensive Income Net Of Tax [Abstract]
Unrealized holding gains (losses) on available-for-sale securities during the period, pre-tax		$ 3,960	$ (4,929)	$ 18,984	$ (14,057)
Reclassification adjustment for (gains) losses included in net income, pre-tax	[1]	(15)	27	18	24
Net other comprehensive income (loss), pre-tax		3,945	(4,902)	19,002	(14,033)
Unrealized holding gains (losses) on available-for-sale securities during the period, tax		(831)	1,036	(3,974)	2,940
Reclassification adjustment for (gains) losses included in net income, tax	[1]	3	(6)	(4)	(5)
Net other comprehensive income (loss), tax		(828)	1,030	(3,978)	2,935
Unrealized holding gains (losses) on available-for-sale securities during the period, after tax		3,129	(3,893)	15,010	(11,117)
Reclassification adjustment for (gains) losses included in net income, after-tax	[1]	(12)	21	14	19
Other comprehensive income (loss), net of tax		$ 3,117	$ (3,872)	$ 15,024	$ (11,098)

[1] Pre-tax reclassification adjustments relating to available-for-sale securities are reported in security gains and the tax impact is included in income tax expense on the consolidated statements of income.