Shareholders' Equity Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 802,869	$ 795,495	$ 800,815	$ 746,599	$ 732,031	$ 734,048	$ 800,815	$ 734,048
OCI before reclassifications							(6,025)	(7,298)
Amounts reclassified from AOCI							56,684	(3,451)
Total other comprehensive income (loss), net of tax	13,814	62,056	(25,211)	(12,705)	3,736	(1,780)	50,659	(10,749)
Ending balance	797,265	802,869	795,495	761,916	746,599	732,031	797,265	761,916
Parent [Member]
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	777,799	770,740	776,538	723,302	709,405	712,663	776,538	712,663
Total other comprehensive income (loss), net of tax	13,814	62,056	(25,211)	(12,705)	3,736	(1,780)
Ending balance	771,896	$ 777,799	770,740	737,289	$ 723,302	709,405	771,896	737,289
Foreign Currency Translation Adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			(157,999)			(157,489)	(157,999)	(157,489)
OCI before reclassifications							(147)	(13,544)
Amounts reclassified from AOCI							52,074	2,443
Total other comprehensive income (loss), net of tax							51,927	(11,101)
Ending balance	(106,072)			(168,590)			(106,072)	(168,590)
Net Unrealized Gain (Loss) on Derivative Instruments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			(723)			1,201	(723)	1,201
OCI before reclassifications							(4,727)	4,995
Amounts reclassified from AOCI							2,570	(5,799)
Total other comprehensive income (loss), net of tax							(2,157)	(804)
Ending balance	(2,880)			397			(2,880)	397
Net Unrealized Gain (Loss) on Nonderivative Instruments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			(14,380)			(14,380)	(14,380)	(14,380)
OCI before reclassifications							0	0
Amounts reclassified from AOCI							0	0
Total other comprehensive income (loss), net of tax							0	0
Ending balance	(14,380)			(14,380)			(14,380)	(14,380)
Pension Benefit Obligation Adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			(31,570)			(25,637)	(31,570)	(25,637)
OCI before reclassifications							(1,151)	1,251
Amounts reclassified from AOCI							2,040	(95)
Total other comprehensive income (loss), net of tax							889	1,156
Ending balance	(30,681)			(24,481)			(30,681)	(24,481)
Accumulated Other Comprehensive Income (Loss)
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance			$ (204,672)			$ (196,305)	(204,672)	(196,305)
Ending balance	$ (154,013)			$ (207,054)			$ (154,013)	$ (207,054)