Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Comprehensive Income Net Of Tax [Abstract]
Unrealized holding gains (losses) on available-for-sale securities during the period, pre-tax		$ 9,203	$ (242)	$ 15,024	$ (9,128)
Reclassification adjustment for (gains) losses included in net income, pre-tax	[1]	(1)	(1)	33	(3)
Net other comprehensive income (loss), pre-tax		9,202	(243)	15,057	(9,131)
Unrealized holding gains (losses) on available-for-sale securities during the period, tax		(1,920)	39	(3,150)	1,904
Reclassification adjustment for (gains) losses included in net income, tax	[1]	0	0	0	1
Net other comprehensive income (loss), tax		(1,920)	39	(3,150)	1,905
Unrealized holding gains (losses) on available-for-sale securities during the period, after tax		7,283	(203)	11,874	(7,224)
Reclassification adjustment for (gains) losses included in net income, after-tax	[1]	(1)	(1)	33	(2)
Other comprehensive income (loss), net of tax		$ 7,282	$ (204)	$ 11,907	$ (7,226)

[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.