Consolidated Statements of Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Non- Controlling Interests
Balance (in shares) at Dec. 31, 2015		36,053,499
Balance at Dec. 31, 2015	$ 594,556	$ 361	$ 199,951	$ 425,574	$ (47,861)	$ 16,531
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	(756)			(370)		(386)
Issuance of common stock upon stock option exercises (in shares)		18,193
Issuance of common stock upon stock option exercises, including tax benefit	13	$ 0	13
Issuance of shares pursuant to restricted stock units (in shares)		12,313
Issuance of shares pursuant to deferred stock unit awards (in Shares)		18,272
Forfeitures of restricted shares (in shares)		(16,494)
Shares repurchased and retired (in shares)		(1,365,249)
Shares repurchased and retired	(25,200)	$ (14)	(25,186)
Equity-based compensation expense	5,616		5,616
Sale of non-controlling interest	(7,278)					(7,278)
Distributions to non-controlling interests						(1,276)
Currency translation adjustment and derivative transactions, net	(5,189)				(5,347)	158
Balance (in shares) at Jun. 30, 2016		34,720,534
Balance at Jun. 30, 2016	$ 560,486	$ 347	180,394	425,204	(53,208)	7,749
Balance (in shares) at Dec. 31, 2016	33,956,304	33,956,304
Balance at Dec. 31, 2016	$ 576,183	$ 340	166,598	455,062	(53,500)	7,683
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	19,931			16,971		2,960
Issuance of shares pursuant to restricted stock units (in shares)		64,111
Issuance of shares pursuant to deferred stock unit awards (in Shares)		17,028
Issuance of shares pursuant to restricted stock units	1	$ 1
Issuance of shares pursuant to performance units (in shares)		49,672
Forfeitures of restricted shares (in shares)		(1,084)
Shares repurchased and retired (in shares)		(965,537)
Shares repurchased and retired	(21,034)	$ (10)	(21,024)
Equity-based compensation expense	6,736		6,736
Distributions to non-controlling interests	(35)					(35)
Currency translation adjustment and derivative transactions, net	$ 16,598				16,578	20
Balance (in shares) at Jun. 30, 2017	33,120,494	33,120,494
Balance at Jun. 30, 2017	$ 598,380	$ 331	$ 152,310	$ 472,033	$ (36,922)	$ 10,628