Stockholders' Equity AOCI (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016	Dec. 31, 2015
Components of accumulated other comprehensive loss
Unrecognized pension and postretirement benefit costs, net of tax	$ (9,583)	$ (9,797)	$ (16,729)	$ (17,185)
Foreign currency translation losses	(17,142)	(16,142)	(16,025)	(16,636)
Total accumulated other comprehensive loss	$ (26,725)	$ (25,939)	$ (32,754)	$ (33,821)