Consolidated Statements of Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Common Stock Restricted Stock Units	Additional Paid-In Capital	Additional Paid-In Capital Restricted Stock Units	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Non- Controlling Interests
Balance at Dec. 31, 2014	$ 645,085	$ 374		$ 217,289		$ 433,641	$ (24,669)	$ 18,450
Balance (in shares) at Dec. 31, 2014		37,360,515
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	25,443					24,793		650
Issuance of common stock upon stock option exercises	1,092	$ 1		1,091
Issuance of common stock upon stock option exercises (in shares)		109,344
Issuance of shares pursuant to restricted stock units (in shares)			12,326
Issuance of shares pursuant to deferred stock unit awards (in shares)		27,779
Forfeitures of restricted shares	(1)	$ (1)
Forfeitures of restricted shares (in shares)		(50,552)
Shares repurchased and retired	(21,941)	$ (12)		(21,929)
Shares repurchased and retired (in shares)		(1,212,181)
Equity-based compensation expense	6,847			6,847
Distributions to non-controlling interests	(472)							(472)
Currency translation adjustment and derivative transactions, net	(21,316)			0			(19,875)	(1,441)
Balance at Sep. 30, 2015	634,737	$ 362		203,298		458,434	(44,544)	17,187
Balance (in shares) at Sep. 30, 2015		36,247,231
Balance at Dec. 31, 2014	645,085	$ 374		217,289		433,641	(24,669)	18,450
Balance (in shares) at Dec. 31, 2014		37,360,515
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Sale of non-controlling interest				0
Balance at Dec. 31, 2015	$ 594,556	$ 361		199,951		425,574	(47,861)	16,531
Balance (in shares) at Dec. 31, 2015	36,053,499	36,053,499
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	$ 11,031					11,697		(666)
Issuance of common stock upon stock option exercises	$ 13	$ 0		13
Issuance of common stock upon stock option exercises (in shares)	18,193	18,193
Issuance of shares pursuant to restricted stock units	$ (23)				$ (23)
Issuance of shares pursuant to restricted stock units (in shares)			14,034
Issuance of shares pursuant to deferred stock unit awards (in shares)		39,660
Forfeitures of restricted shares	0	$ 0
Forfeitures of restricted shares (in shares)		(18,499)
Shares repurchased and retired	(36,597)	$ (20)		(36,577)
Shares repurchased and retired (in shares)		(1,967,347)
Equity-based compensation expense	7,689			7,689
Sale of non-controlling interest	(7,278)							(7,278)
Distributions to non-controlling interests	(1,276)							(1,276)
Currency translation adjustment and derivative transactions, net	(318)						(391)	73
Balance at Sep. 30, 2016	$ 567,797	$ 341		$ 171,053		$ 437,271	$ (48,252)	$ 7,384
Balance (in shares) at Sep. 30, 2016	34,139,540	34,139,540