CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock, at cost	Non-controlling interests
Balance (in shares) at Dec. 31, 2016		25,413
Balance at Dec. 31, 2016	$ 62,194	$ 25,413	$ 107,288	$ 333,786	$ (1,745)	$ (403,953)	$ 1,405
Increase (Decrease) in Equity
Net income (loss)	16,882			15,580			1,302
Other comprehensive income, net of tax	5,742				5,742
Distributions to non-controlling interest holders	(1,056)						(1,056)
Share-based compensation expense	1,858		1,858
Exercise of stock options and issuance of restricted shares	765			(5,014)		5,779
Treasury shares withheld for the payment of tax on restricted share issuances and stock option exercises	(1,089)			(1,494)		405
Repurchase of shares	(18,573)					(18,573)
Balance (in shares) at Jun. 30, 2017		25,413
Balance at Jun. 30, 2017	66,723	$ 25,413	110,078	341,926	3,997	(416,342)	1,651
Balance (in shares) at Dec. 31, 2017		25,413
Balance at Dec. 31, 2017	339,985	$ 25,413	112,475	626,600	733	(426,609)	1,373
Increase (Decrease) in Equity
Net income (loss)	(1,352)			(2,564)			1,212
Distributions to non-controlling interest holders	(1,181)						(1,181)
Share-based compensation expense	4,111		4,111
Exercise of stock options and issuance of restricted shares	2,707			(17,237)		19,944
Treasury shares withheld for the payment of tax on restricted share issuances and stock option exercises	(410)			(816)		406
Repurchase of shares	(21,121)					(21,121)
Balance (in shares) at Jun. 30, 2018		25,413
Balance at Jun. 30, 2018	$ 312,291	$ 25,413	$ 116,586	$ 596,268	$ 0	$ (427,380)	$ 1,404