Consolidated Statements of Stockholders' Equity - USD ($) shares in Thousands, $ in Thousands	Common Stock	Additional Paid-in Capital	Foreign Currency Translation	Retained Earnings	Non-controlling Interest	Total
Beginning Balance at Dec. 31, 2018	$ 38	$ 97,418	$ (3,449)	$ 512,783	$ 512	$ 607,302
Beginning Balance (in shares) at Dec. 31, 2018	38,164
Stock issued from equity plans		(1,707)				(1,707)
Stock issued from equity plans (in shares)	72
Stock-based compensation		3,199				3,199
Other comprehensive income (loss)			(2,028)			(2,028)
Net income				15,370	8	15,378
Ending Balance at Mar. 31, 2019	$ 38	98,910	(5,477)	528,153	520	622,144
Ending Balance (in shares) at Mar. 31, 2019	38,236
Beginning Balance at Dec. 31, 2018	$ 38	97,418	(3,449)	512,783	512	607,302
Beginning Balance (in shares) at Dec. 31, 2018	38,164
Net income						47,075
Ending Balance at Jun. 30, 2019	$ 38	100,512	(4,871)	559,839	531	656,049
Ending Balance (in shares) at Jun. 30, 2019	38,305
Beginning Balance at Mar. 31, 2019	$ 38	98,910	(5,477)	528,153	520	622,144
Beginning Balance (in shares) at Mar. 31, 2019	38,236
Stock issued from equity plans		665				665
Stock issued from equity plans (in shares)	69
Stock-based compensation		937				937
Other comprehensive income (loss)			606			606
Net income				31,686	11	31,697
Ending Balance at Jun. 30, 2019	$ 38	100,512	(4,871)	559,839	531	656,049
Ending Balance (in shares) at Jun. 30, 2019	38,305
Adoption of new accounting standards				(102)		(102)
Beginning Balance at Dec. 31, 2019	$ 38	104,849	(5,897)	577,724	546	$ 677,260
Beginning Balance (in shares) at Dec. 31, 2019	38,358					38,358
Stock issued from equity plans		(2,171)				$ (2,171)
Stock issued from equity plans (in shares)	64
Stock-based compensation		3,048				3,048
Stock buyback		(7,248)				(7,248)
Stock buyback (in shares)	(170)
Other comprehensive income (loss)			(2,907)			(2,907)
Net income				18,063	15	18,078
Ending Balance at Mar. 31, 2020	$ 38	98,478	(8,804)	595,685	561	685,958
Ending Balance (in shares) at Mar. 31, 2020	38,252
Beginning Balance at Dec. 31, 2019	$ 38	104,849	(5,897)	577,724	546	$ 677,260
Beginning Balance (in shares) at Dec. 31, 2019	38,358					38,358
Stock buyback						$ (7,248)
Net income						47,206
Ending Balance at Jun. 30, 2020	$ 38	102,094	(9,148)	624,829	545	$ 718,358
Ending Balance (in shares) at Jun. 30, 2020	38,325					38,325
Beginning Balance at Mar. 31, 2020	$ 38	98,478	(8,804)	595,685	561	$ 685,958
Beginning Balance (in shares) at Mar. 31, 2020	38,252
Stock issued from equity plans		779				779
Stock issued from equity plans (in shares)	73
Stock-based compensation		2,837				2,837
Other comprehensive income (loss)			(344)			(344)
Net income				29,144	(16)	29,128
Ending Balance at Jun. 30, 2020	$ 38	$ 102,094	$ (9,148)	$ 624,829	$ 545	$ 718,358
Ending Balance (in shares) at Jun. 30, 2020	38,325					38,325