Comprehensive Income - Components of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Accumulated other comprehensive income (loss)
Beginning balance	$ (2,933)	$ (2,642)
Other comprehensive income (loss) before reclassification, net of tax	1,001	122
Amounts reclassified from AOCI, net of tax	(194)	(34)
Net current period OCI	807	88
Ending balance	(2,126)	(2,554)
Available-for-sale securities, Unrealized holding gains
Accumulated other comprehensive income (loss)
Beginning balance	(363)	(406)
Other comprehensive income (loss) before reclassification, net of tax	1,346	324
Amounts reclassified from AOCI, net of tax	(229)	(72)
Net current period OCI	1,117	252
Ending balance	754	(154)
Defined benefit pension plan items, Change in defined benefit pension plan
Accumulated other comprehensive income (loss)
Beginning balance	(2,570)	(2,236)
Other comprehensive income (loss) before reclassification, net of tax	(345)	(202)
Amounts reclassified from AOCI, net of tax	35	38
Net current period OCI	(310)	(164)
Ending balance	$ (2,880)	$ (2,400)