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