Condensed Consolidated Statements of Changes in Equity - USD ($) $ in Thousands	Total	Cumulative Effect, Period of Adoption, Adjustment	Common Stock Common Stock Class A	Common Stock Common Stock Class B	Additional Paid-in Capital	Retained Earnings	Retained Earnings Cumulative Effect, Period of Adoption, Adjustment	Retained Earnings, Appropriated	AOCI Attributable to Parent	Noncontrolling Interests
Beginning balance (in shares) at Dec. 31, 2021			53,608,929	5,087,814
Beginning balance at Dec. 31, 2021	$ 811,665		$ 5	$ 1	$ 595,045	$ 63,732		$ 8,312	$ 9,109	$ 135,461
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	9,305					6,450				2,855
Foreign currency translation adjustment	(37,918)								(31,742)	(6,176)
Exercise of stock options (in shares)			531,874
Exercise of stock options	750				750
Stock-based compensation	3,343				3,343
Conversion of class B common stock to Class A common stock (in shares)			1,002	(1,002)
Conversion of Class B common stock to Class A common stock	1,002
Ending balance (in shares) at Jun. 30, 2022			54,141,805	5,086,812
Ending balance at Jun. 30, 2022	787,145		$ 5	$ 1	599,138	70,182		8,312	(22,633)	132,140
Beginning balance (in shares) at Mar. 31, 2022			54,035,280	5,086,812
Beginning balance at Mar. 31, 2022	808,774		$ 5	$ 1	597,143	57,946		8,312	10,979	134,388
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	16,748					12,236				4,512
Foreign currency translation adjustment	(40,372)								(33,612)	(6,760)
Exercise of stock options (in shares)			106,525
Exercise of stock options	26				26
Stock-based compensation	1,969				1,969
Ending balance (in shares) at Jun. 30, 2022			54,141,805	5,086,812
Ending balance at Jun. 30, 2022	787,145		$ 5	$ 1	599,138	70,182		8,312	(22,633)	132,140
Beginning balance (in shares) at Dec. 31, 2022			54,655,286	5,021,811
Beginning balance at Dec. 31, 2022	812,171
Beginning balance at Dec. 31, 2022	813,779	$ (1,769)	$ 5	$ 1	604,089	96,034	$ (1,769)	16,881	(40,546)	137,315
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	42,560					33,970				8,590
Foreign currency translation adjustment	(25,846)								(21,370)	(4,476)
Exercise of stock options (in shares)			296,204
Exercise of stock options	4,525				4,525
Shanghai dividend accrual	(3,951)					(3,951)
Stock-based compensation	4,085				4,085
Conversion of Class B common stock to Class A common stock	0
Ending balance (in shares) at Jun. 30, 2023			54,951,490	5,021,811
Ending balance at Jun. 30, 2023	833,383
Ending balance at Jun. 30, 2023	833,383		$ 5	$ 1	612,699	124,284		16,881	(61,916)	141,429
Beginning balance (in shares) at Mar. 31, 2023			54,818,355	5,021,811
Beginning balance at Mar. 31, 2023	832,705		$ 5	$ 1	606,398	101,410		16,881	(32,768)	140,778
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	33,597					26,825				6,772
Foreign currency translation adjustment	(35,269)								(29,148)	(6,121)
Exercise of stock options (in shares)			133,135
Exercise of stock options	4,284				4,284
Shanghai dividend accrual	(3,951)					(3,951)
Stock-based compensation	2,017				2,017
Ending balance (in shares) at Jun. 30, 2023			54,951,490	5,021,811
Ending balance at Jun. 30, 2023	833,383
Ending balance at Jun. 30, 2023	$ 833,383		$ 5	$ 1	$ 612,699	$ 124,284		$ 16,881	$ (61,916)	$ 141,429