Other Income, Net (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Other Income and Expenses [Abstract]
Interest income	$ 244	$ 332	$ 368
Other nonoperating income	208	789	321
Insurance Policy Expense (Income), Net	22	(228)	(409)
Other nonoperating expense	(13)	(10)	(10)
Other income, net	$ 461	$ 883	$ 270