Shareholders' Equity Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	$ (170,478)
Total other comprehensive income (loss), net of tax	17,883	$ 15,709
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	(152,595)
Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	(170,478)	(229,327)
OCI before reclassifications	17,483	15,076
Amounts reclassified from AOCI	400	633
Total other comprehensive income (loss), net of tax	17,883	15,709
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	(152,595)	(213,618)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	(128,648)	(182,986)
OCI before reclassifications	16,300	15,016
Amounts reclassified from AOCI	0	0
Total other comprehensive income (loss), net of tax	16,300	15,016
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	(112,348)	(167,970)
Accumulated Other Comprehensive Income, Net Unrealized Gain (Loss) on Derivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	966	43
OCI before reclassifications	1,183	60
Amounts reclassified from AOCI	(14)	232
Total other comprehensive income (loss), net of tax	1,169	292
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	2,135	335
Accumulated Other Comprehensive Income, Net Unrealized Gain (Loss) on Nonderivative Instruments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	(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
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	(14,380)	(14,380)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax, Beginning of Period	(28,416)	(32,004)
OCI before reclassifications	0	0
Amounts reclassified from AOCI	414	401
Total other comprehensive income (loss), net of tax	414	401
Accumulated Other Comprehensive Income (Loss), Net of Tax, End of Period	$ (28,002)	$ (31,603)