Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended			6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019		Jun. 30, 2020		Jun. 30, 2019
Comprehensive Income Net Of Tax [Abstract]
Unrealized holding gains (losses) on available-for-sale securities during the period, pre-tax		$ 25,411	$ 9,203		$ 13,194		$ 15,024
Reclassification adjustment for (gains) losses included in net income, pre-tax	[1]	(14)	(1)		(270)		33
Net other comprehensive income (loss), pre-tax		25,397	9,202		12,924		15,057
Unrealized holding gains (losses) on available-for-sale securities during the period, tax		(5,336)	(1,920)		(2,771)		(3,150)
Reclassification adjustment for (gains) losses included in net income, tax	[1]	3	0		57		0
Net other comprehensive income (loss), tax		(5,333)	(1,920)		(2,714)		(3,150)
Unrealized holding gains (losses) on available-for-sale securities during the period, after tax		20,075	7,283		10,423		11,874
Reclassification adjustment for (gains) losses included in net income, after-tax		(11)	(1)	[1]	(213)	[1]	33	[1]
Other comprehensive income, net of tax		$ 20,064	$ 7,282		$ 10,210		$ 11,907

[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.