Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciles the accumulated liability for the benefit obligation
Beginning balance	$ 2,760	$ 2,549	$ 2,396
Benefit expense	359	369	308
Benefit payments	(162)	(158)	(155)
Ending balance	$ 2,957	$ 2,760	$ 2,549