Shareholders' Equity - Components Of Accumulated OCI (Details) - USD ($) $ in Thousands		12 Months Ended
	Jan. 01, 2018	Dec. 31, 2018	Dec. 31, 2017
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative foreign currency translation adjustment		$ (69,855)	$ (62,689)
Net unrealized loss on hedges, net of tax		(4,109)	(7,507)
Unrealized gain on note receivable, net of tax		0	409
Accumulated other comprehensive loss		(73,964)	(69,787)
Deferred tax assets		1,000	4,000
Reclassification of stranded tax effect from accumulated OCI to retained earnings		0
Deferred tax liabilities			$ 200
AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of stranded tax effect from accumulated OCI to retained earnings		1,530
Retained Earnings
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of stranded tax effect from accumulated OCI to retained earnings		$ (1,530)
ASU No. 2018-02 | AOCI
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of stranded tax effect from accumulated OCI to retained earnings	$ 1,500
ASU No. 2018-02 | AOCI | Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of stranded tax effect from accumulated OCI to retained earnings	1,600
ASU No. 2018-02 | AOCI | Note Receivable
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of stranded tax effect from accumulated OCI to retained earnings	(100)
ASU No. 2018-02 | Retained Earnings
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of stranded tax effect from accumulated OCI to retained earnings	(1,500)
ASU No. 2018-02 | Retained Earnings | Hedges
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of stranded tax effect from accumulated OCI to retained earnings	(1,600)
ASU No. 2018-02 | Retained Earnings | Note Receivable
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification of stranded tax effect from accumulated OCI to retained earnings	$ 100