Condensed Consolidated Statements of Shareholders' Equity Statement - USD ($) shares in Thousands, $ in Thousands	Total	Common Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Balance, beginning of period at Dec. 31, 2017	$ 1,567,393	$ 1,284,274	$ 352,906	$ (69,787)
Balance, beginning of period (in shares) at Dec. 31, 2017		147,740
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(2,560)		(2,560)
Reclassification of stranded tax effect to retained earnings	0		1,530	(1,530)
Foreign currency translation adjustments	4,691			4,691
Unrealized gain on hedges, net of tax	2,965			2,965
Unrealized loss on note receivable, net of tax	(497)			(497)
Equity component of debt discount on convertible senior notes	15,424	$ 15,424
Activity in company stock plans, net and other	(862)	$ (862)
Activity in company stock plans, net and other (in shares)		340
Share-based compensation	2,463	$ 2,463
Balance, end of period at Mar. 31, 2018	1,589,018	$ 1,301,299	351,876	(64,157)
Balance, end of period (in shares) at Mar. 31, 2018		148,080
Balance, beginning of period at Dec. 31, 2018	1,617,779	$ 1,308,709	383,034	(73,964)
Balance, beginning of period (in shares) at Dec. 31, 2018		148,203
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	1,318		1,318
Reclassification of deferred gain from sale and leaseback transaction to retained earnings	4,560		4,560
Foreign currency translation adjustments	2,802			2,802
Unrealized gain on hedges, net of tax	1,355			1,355
Unrealized loss on note receivable, net of tax	0
Activity in company stock plans, net and other	(659)	$ (659)
Activity in company stock plans, net and other (in shares)		582
Share-based compensation	2,688	$ 2,688
Balance, end of period at Mar. 31, 2019	$ 1,629,843	$ 1,310,738	$ 388,912	$ (69,807)
Balance, end of period (in shares) at Mar. 31, 2019		148,785