Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Total	Restricted stock units	Common stock	Restricted stock units Restricted stock units	Additional paid-in capital	Exchangeable shares of subsidiary	Retained earnings	Accumulated other comprehensive income (loss)	Treasury stock	Parent
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of the change in accounting principle related to revenue recognition | Accounting Standards Update 2014-09							$ 0
Retained earnings, beginning of the period, as adjusted							109,860
Beginning Balance at Dec. 31, 2015			$ 405	$ 84,969	$ 697,607	$ 1,958	109,860	$ (28,405)	$ (583,038)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock issued			9		44,789
Restricted stock units recognized, net of forfeitures				45,880
Restricted stock units delivered				(44,942)
Tax benefit (expense)					(7,668)		2,785
Dividends							(61,609)
Net income (loss)	$ 60,762						60,762
Currency translation adjustment, net of tax	(3,993)							(3,993)
Repurchased									(28,186)
Ending Balance at Dec. 31, 2016			414	85,907	734,728	1,958	111,798	(32,398)	(611,224)	$ 291,183
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of the change in accounting principle related to revenue recognition | Accounting Standards Update 2014-09							0
Retained earnings, beginning of the period, as adjusted							111,798
Common stock issued			24		65,231
Restricted stock units recognized, net of forfeitures				40,597
Restricted stock units delivered				(45,992)
Tax benefit (expense)					847		0
Dividends							(47,552)
Net income (loss)	(26,651)						(26,651)
Currency translation adjustment, net of tax	10,176							10,176
Repurchased		$ (13,800)							(79,561)
Ending Balance at Dec. 31, 2017			438	80,512	800,806	1,958	37,595	(22,222)	(690,785)	208,302
Retained earnings	37,595
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of the change in accounting principle related to revenue recognition | Accounting Standards Update 2014-09							(7,645)
Retained earnings, beginning of the period, as adjusted							29,950
Common stock issued			12		45,915
Restricted stock units recognized, net of forfeitures				37,941
Restricted stock units delivered				(46,857)
Tax benefit (expense)					0		0
Dividends							(5,745)
Net income (loss)	39,222						39,222
Currency translation adjustment, net of tax	(13,483)							(13,483)
Repurchased		$ (8,700)							(195,299)
Ending Balance at Dec. 31, 2018			$ 450	$ 71,596	$ 846,721	$ 1,958	$ 63,427	$ (35,705)	$ (886,084)	$ 62,363
Retained earnings	$ 63,427