Stockholders' Equity AOCI (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Components of accumulated other comprehensive loss
Unrecognized pension and postretirement benefit costs, net of tax	$ (15,817)	$ (16,273)	$ (17,185)	$ (23,593)	$ (24,263)	$ (27,122)
Foreign currency translation losses	(17,133)	(20,100)	(16,636)	(17,627)	(14,686)	(9,994)
Total accumulated other comprehensive loss	$ (32,950)	$ (36,373)	$ (33,821)	$ (41,220)	$ (38,949)	$ (37,116)