Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Comprehensive Income Net Of Tax [Abstract]
Unrealized holding gains on available-for-sale securities during the period, pre-tax		$ 5,020	$ (5,447)	$ 8,377	$ (3,136)
Reclassification adjustment for (gains) losses included in net income, pre-tax	[1]	(41)	(35)	(41)	(45)
Net unrealized holding gains (losses)		4,979	(5,482)	8,336	(3,181)
Unrealized holding gains on available-for-sale securities during the period, tax		(1,759)	1,907	(2,934)	1,097
Reclassification adjustment for (gains) losses included in net income, tax	[1]	14	12	14	16
Net unrealized gains on available-for-sale securities, tax		(1,745)	1,919	(2,920)	1,113
Unrealized holding gains on available-for-sale securities during the period, after-tax		3,261	(3,540)	5,443	(2,039)
Reclassification adjustment for (gains) losses included in net income, after-tax	[1]	(27)	(23)	(27)	(29)
Net unrealized gains on available-for-sale securities, after-tax		$ 3,234	$ (3,563)	$ 5,416	$ (2,068)

[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.