Other Income, Net (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Other Income and Expenses [Abstract]
Interest income	$ 162	$ 729	$ 537	$ 1,375
Other nonoperating income	607	573	1,904	2,448
Insurance policy income (expense)	453	418	233	(394)
Other income, net	$ 1,222	$ 1,720	$ 2,674	$ 3,429