Reclassifications Out of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	$ 517,128
Other comprehensive income (loss)	15,840	$ (21,521)
Balance at end of period	540,640
Accumulated Defined Benefit Plans Adjustment Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(119,389)	(125,570)
Tax benefit	(1,044)	(1,417)
Total amount reclassified from Accumulated other comprehensive loss, net of tax	(1,892)	(2,529)
Balance at end of period	(117,497)	(123,041)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amounts reclassified from Accumulated other comprehensive loss	(90)	17
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amounts reclassified from Accumulated other comprehensive loss	3,026	3,929
Accumulated Foreign Currency Adjustment Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(88,810)	(41,160)
Other comprehensive income (loss)	13,624	(23,792)
Balance at end of period	(73,083)	(64,952)
Accumulated Other Comprehensive (Loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification into earnings	2,103	0
Accumulated Foreign Currency Adjustment Attributable to Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(3,616)	(2,199)
Other comprehensive income (loss)	324	(258)
Balance at end of period	$ (3,292)	$ (2,457)