Stockholders' Equity AOCI (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Jun. 30, 2015	Dec. 31, 2014	Jun. 30, 2014	Dec. 31, 2013
Components of accumulated other comprehensive loss
Total accumulated other comprehensive loss		$ (49,669)	$ (19,420)	$ (49,669)	$ (19,420)	$ (47,398)	$ (45,565)	$ (17,610)	$ (18,743)
Other comprehensive (loss) income before reclassifications		(2,941)	(2,064)	(7,633)	(1,438)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[1]	670	254	3,529	761
Net current period other comprehensive income (loss)		(2,271)	(1,810)	(4,104)	(677)
Foreign Currency Items
Components of accumulated other comprehensive loss
Foreign currency translation losses		(17,627)	(6,055)	(17,627)	(6,055)	(14,686)	(9,994)	(3,991)	(4,617)
Other comprehensive (loss) income before reclassifications		(2,941)	(2,064)	(7,633)	(1,438)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[1]	0	0	0	0
Net current period other comprehensive income (loss)		(2,941)	(2,064)	(7,633)	(1,438)
Defined Benefit Pension and Postretirement Items
Components of accumulated other comprehensive loss
Unrecognized pension and postretirement benefit costs, net of tax		(32,042)	(13,365)	(32,042)	(13,365)	$ (32,712)	$ (35,571)	$ (13,619)	$ (14,126)
Other comprehensive (loss) income before reclassifications		0	0	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[1]	670	254	3,529	761
Net current period other comprehensive income (loss)		$ 670	$ 254	$ 3,529	$ 761

[1] See reclassifications from accumulated other comprehensive loss table for details of reclassification from accumulated other comprehensive loss for the nine month periods ended September 30, 2015 and 2014, respectively.