Balance Sheet Components - Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 554,341
Other comprehensive income (loss) before reclassifications	2,873	$ 1,099
Amounts reclassified from other comprehensive income (loss), net of tax	(199)	6
Net current-period other comprehensive income (loss), net of tax	2,674	1,105
Ending balance	574,502
Foreign currency translation adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(6,954)	(10,764)
Other comprehensive income (loss) before reclassifications	2,472	923
Amounts reclassified from other comprehensive income (loss), net of tax		0
Net current-period other comprehensive income (loss), net of tax	2,472	923
Ending balance	(4,482)	(9,841)
Unrealized gain (loss) on interest rate swap hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	841	1,245
Other comprehensive income (loss) before reclassifications	401	176
Amounts reclassified from other comprehensive income (loss), net of tax	(199)	6
Net current-period other comprehensive income (loss), net of tax	202	182
Ending balance	1,043	1,427
AOCI Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(6,113)	(9,519)
Ending balance	$ (3,439)	$ (8,414)

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount before tax and reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Amount before tax of other comprehensive income (loss) attributable to parent entity.

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Amount before tax of reclassification adjustments of other comprehensive income (loss) attributable to parent.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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