Reclassifications Out of Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	$ 809,891
Total amount reclassified from Accumulated other comprehensive loss, net of tax	0	$ 720
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax	(5)	(62)
Other comprehensive income (loss)	(6,516)	(19,187)
Balance at end of period	822,890
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	(115,552)	(124,848)
Tax benefit	(1,084)	(1,067)
Total amount reclassified from Accumulated other comprehensive loss, net of tax	3,712	3,102
Balance at end of period	(111,840)	(121,746)
Accumulated Defined Benefit Plans Adjustment Attributable to Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	0	0
Tax benefit	0	0
Total amount reclassified from Accumulated other comprehensive loss, net of tax	0	0
Balance at end of period	0	0
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	(24)	(52)
Accumulated Defined Benefit Plans Adjustment, Net Prior Service Attributable to Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amounts reclassified from Accumulated other comprehensive loss	0	0
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	4,820	4,221
Accumulated Defined Benefit Plans Adjustment, Net Gain (Loss) Attributable to Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Amounts reclassified from Accumulated other comprehensive loss	0	0
Accumulated Net Investment Gain (Loss) Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(1)	6
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax	(5)	(62)
Balance at end of period	(6)	(56)
Accumulated Net Investment Gain (Loss) Attributable to Noncontrolling Interest
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	0	0
Other Comprehensive Income (Loss), Securities, Available-for-Sale, Unrealized Holding Gain (Loss) Arising During Period, after Tax	0	0
Balance at end of period	0	0
Accumulated Foreign Currency Adjustment Attributable to Parent
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance at beginning of period	(66,844)	(89,161)
Total amount reclassified from Accumulated other comprehensive loss, net of tax	0	720
Other comprehensive income (loss)	(10,258)	(22,832)
Balance at end of period	(77,102)	(111,273)
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	582	423
Total amount reclassified from Accumulated other comprehensive loss, net of tax	0	0
Other comprehensive income (loss)	35	(115)
Balance at end of period	$ 617	$ 308