Stockholders' Equity AOCI (Details) - USD ($) $ in Thousands	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014
Components of accumulated other comprehensive loss
Unrecognized pension and postretirement benefit costs, net of tax	$ (16,273)	$ (16,729)	$ (17,185)	$ (24,263)	$ (26,100)	$ (27,122)
Foreign currency translation losses	(20,100)	(16,025)	(16,636)	(14,686)	(14,308)	(9,994)
Total accumulated other comprehensive loss	$ (36,373)	$ (32,754)	$ (33,821)	$ (38,949)	$ (40,408)	$ (37,116)