Consolidated Statements of Equity - USD ($) $ in Thousands	Common Shares in Treasury [Member]	Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Non-controlling Interests [Member]	Total
Beginning Balances at Dec. 31, 2016	$ (160,936)	$ 93,436	$ 306,566	$ 114,690	$ (106,643)	$ 7,919	$ 255,032
Beginning Balances, shares at Dec. 31, 2016	9,996,000
Net income				57,054		714	57,768
Other comprehensive income (loss)					31,175	352	$ 31,527
Purchase of treasury stock, shares							0
Stock-based compensation transactions	$ 13,880		(4,408)				$ 9,472
Stock-based compensation transactions, shares	(610,000)
Change in ownership interest						3,355	3,355
Distributions to noncontrolling interests						(474)	(474)
Ending Balances at Dec. 31, 2017	$ (147,056)	93,436	302,158	171,744	(75,468)	11,866	356,680
Ending Balances, shares at Dec. 31, 2017	9,386,000
Net income				80,093		853	80,946
Other comprehensive income (loss)					(29,893)	(501)	(30,394)
Purchase of treasury stock	$ (28,807)						$ (28,807)
Purchase of treasury stock, shares	1,471,000						1,470,791
Stock-based compensation transactions	$ 10,318		(4,824)				$ 5,494
Stock-based compensation transactions, shares	(424,000)
Change in ownership interest			789
Change in ownership interest						(2,228)	(1,439)
Distributions to noncontrolling interests						(772)	(772)
Ending Balances at Dec. 31, 2018	$ (165,545)	93,436	298,123	255,978	(105,361)	9,218	385,849
Ending Balances, shares at Dec. 31, 2018	10,433,000
Adjustments for accounting standard update 2016-16				4,141			4,141
Net income				6,038		1,377	7,415
Other comprehensive income (loss)					(4,015)	(115)	(4,130)
Purchase of treasury stock	$ (25,000)						$ (25,000)
Purchase of treasury stock, shares	1,441,000						1,440,678
Stock-based compensation transactions	$ 10,302		(3,580)				$ 6,722
Stock-based compensation transactions, shares	(443,000)
Distributions to noncontrolling interests						(654)	(654)
Ending Balances at Dec. 31, 2019	$ (180,243)	$ 93,436	$ 294,543	$ 262,016	$ (109,376)	$ 9,826	$ 370,202
Ending Balances, shares at Dec. 31, 2019	11,431,000