CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common Shares	Additional Paid-In Capital	Accumulated Other Comprehensive Income (Loss)	Accumulated Deficit
Balance at Dec. 31, 2015	$ 244,701	$ 423,856	$ 29,225	$ (18,830)	$ (189,550)
Balance (in shares) at Dec. 31, 2015		34,345
Net income	22,003				22,003
Common stock issued under stock plans	181		181
Common stock issued under stock plans (in shares)		351
Shares withheld for taxes on vested stock awards	(1,789)		(1,789)
Shares withheld for taxes on vested stock awards (in shares)		(129)
Repurchases of common stock	(1,634)		(1,634)
Repurchases of common stock (in shares)		(109)
Share-based compensation	4,293		4,293
Other comprehensive income (loss), net of tax	(8,885)			(8,885)
Balance at Dec. 31, 2016	258,870	$ 423,856	30,276	(27,715)	(167,547)
Balance (in shares) at Dec. 31, 2016		34,458
Net income	60,051				60,051
Redeemable noncontrolling interest redemption value adjustment (Note 5)	(20,244)				(20,244)
Common stock issued under stock plans (in shares)		228
Shares withheld for taxes on vested stock awards	(2,090)		(2,090)
Shares withheld for taxes on vested stock awards (in shares)		(77)
Repurchases of common stock	(370)		(370)
Repurchases of common stock (in shares)		(14)
Share-based compensation	5,493		5,493
Other comprehensive income (loss), net of tax	9,835			9,835
Balance at Dec. 31, 2017	311,545	$ 423,856	33,309	(17,880)	(127,740)
Balance (in shares) at Dec. 31, 2017		34,595
Net income	49,109				49,109
Redeemable noncontrolling interest redemption value adjustment (Note 5)	1,781				1,781
Acquisition of noncontrolling interest	14,401		14,401
Acquisition of noncontrolling interest (in shares)		213
Common stock issued under stock plans (in shares)		231
Shares withheld for taxes on vested stock awards	(3,556)		(3,556)
Shares withheld for taxes on vested stock awards (in shares)		(64)
Repurchases of common stock	(5,850)		(5,850)
Repurchases of common stock (in shares)		(89)
Share-based compensation	7,714		7,714
Adoption of ASU 2016-16 | ASU 2016-16	(2,242)				(2,242)
Other comprehensive income (loss), net of tax	(4,647)			(4,647)
Balance at Dec. 31, 2018	$ 368,255	$ 423,856	$ 46,018	$ (22,527)	$ (79,092)
Balance (in shares) at Dec. 31, 2018		34,886