Consolidated Statements of Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Total
Balance (in shares) at Dec. 31, 2019	26,786,459
Balance at Dec. 31, 2019	$ 27	$ 268,059	$ 324,722	$ (7,018)	$ 585,790
Common shares issued on exercise of options and other, net of shares withheld for tax obligations (in shares)	23,525
Common shares issued on exercise of options and other, net of shares withheld for tax obligations	$ 0	(902)	0	0	(902)
Stock-based compensation expense	0	3,033	0	0	3,033
Net income	0	0	13,984	0	13,984
Other comprehensive loss
Foreign currency translation adjustment	$ 0	0	0	(2,980)	(2,980)
Comprehensive income					11,004
Common shares issued on exercise of options and other, net of shares withheld for tax obligations (in shares)	23,525
Common shares issued on exercise of options and other, net of shares withheld for tax obligations	$ 0	(902)	0	0	(902)
Stock-based compensation expense	$ 0	3,033	0	0	3,033
Repurchases of common stock (in shares)	(161,460)
Repurchases of common stock	$ 0	(1,616)	(9,569)	0	(11,185)
Net income	0	0	13,984	0	13,984
Foreign currency translation adjustment	$ 0	0	0	(2,980)	(2,980)
Balance (in shares) at Dec. 31, 2019	26,786,459
Balance at Dec. 31, 2019	$ 27	268,059	324,722	(7,018)	585,790
Balance (in shares) at Mar. 31, 2020	26,648,524
Balance at Mar. 31, 2020	$ 27	268,574	329,137	(9,998)	587,740
Balance (in shares) at Dec. 31, 2019	26,786,459
Balance at Dec. 31, 2019	$ 27	268,059	324,722	(7,018)	585,790
Net income					41,288
Other comprehensive loss
Comprehensive income					41,782
Net income					41,288
Balance (in shares) at Dec. 31, 2019	26,786,459
Balance at Dec. 31, 2019	$ 27	268,059	324,722	(7,018)	585,790
Balance (in shares) at Sep. 30, 2020	26,753,545
Balance at Sep. 30, 2020	$ 27	278,996	353,322	(6,524)	625,821
Balance (in shares) at Mar. 31, 2020	26,648,524
Balance at Mar. 31, 2020	$ 27	268,574	329,137	(9,998)	587,740
Common shares issued on exercise of options and other, net of shares withheld for tax obligations (in shares)	96,186
Common shares issued on exercise of options and other, net of shares withheld for tax obligations	$ 0	400	0	0	400
Stock-based compensation expense	0	3,639	0	0	3,639
Net income	0	0	12,607	0	12,607
Other comprehensive loss
Foreign currency translation adjustment		0	0	364	364
Comprehensive income					12,971
Common shares issued on exercise of options and other, net of shares withheld for tax obligations (in shares)	96,186
Common shares issued on exercise of options and other, net of shares withheld for tax obligations	$ 0	400	0	0	400
Stock-based compensation expense	$ 0	3,639	0	0	3,639
Repurchases of common stock (in shares)	(38,154)
Repurchases of common stock	$ 0	(382)	(3,119)	0	(3,501)
Net income	0	0	12,607	0	12,607
Foreign currency translation adjustment		0	0	364	364
Balance (in shares) at Mar. 31, 2020	26,648,524
Balance at Mar. 31, 2020	$ 27	268,574	329,137	(9,998)	587,740
Balance (in shares) at Jun. 30, 2020	26,706,556
Balance at Jun. 30, 2020	$ 27	272,231	338,625	(9,634)	601,249
Common shares issued on exercise of options and other, net of shares withheld for tax obligations (in shares)	46,989
Common shares issued on exercise of options and other, net of shares withheld for tax obligations	$ 0	2,820	0	0	2,820
Stock-based compensation expense	0	3,945	0	0	3,945
Net income	0	0	14,697	0	14,697
Other comprehensive loss
Foreign currency translation adjustment		0	0	3,110	3,110
Comprehensive income					17,807
Common shares issued on exercise of options and other, net of shares withheld for tax obligations (in shares)	46,989
Common shares issued on exercise of options and other, net of shares withheld for tax obligations	$ 0	2,820	0	0	2,820
Stock-based compensation expense	0	3,945	0	0	3,945
Repurchases of common stock	0	0	0	0	0
Net income	0	0	14,697	0	14,697
Foreign currency translation adjustment		0	0	3,110	3,110
Balance (in shares) at Jun. 30, 2020	26,706,556
Balance at Jun. 30, 2020	$ 27	272,231	338,625	(9,634)	601,249
Balance (in shares) at Sep. 30, 2020	26,753,545
Balance at Sep. 30, 2020	$ 27	278,996	353,322	(6,524)	$ 625,821
Balance (in shares) at Dec. 31, 2020	26,776,796				26,776,796
Balance at Dec. 31, 2020	$ 27	284,848	362,901	(3,420)	$ 644,356
Common shares issued on exercise of options and other, net of shares withheld for tax obligations (in shares)	48,955
Common shares issued on exercise of options and other, net of shares withheld for tax obligations		(290)			(290)
Common shares issued for Hubs acquisition (in shares)	863,995
Common shares issued for Hubs acquisition	$ 1	166,708			166,709
Stock-based compensation expense		5,620			5,620
Net income			3,712		3,712
Other comprehensive loss
Foreign currency translation adjustment				(6,842)	(6,842)
Net unrealized gains (losses) on investments in securities				166	166
Comprehensive income					(2,964)
Common shares issued on exercise of options and other, net of shares withheld for tax obligations (in shares)	48,955
Common shares issued on exercise of options and other, net of shares withheld for tax obligations		(290)			(290)
Stock-based compensation expense		5,620			5,620
Net income			3,712		3,712
Foreign currency translation adjustment				(6,842)	$ (6,842)
Balance (in shares) at Dec. 31, 2020	26,776,796				26,776,796
Balance at Dec. 31, 2020	$ 27	284,848	362,901	(3,420)	$ 644,356
Balance (in shares) at Mar. 31, 2021	27,689,746
Balance at Mar. 31, 2021	$ 28	456,886	366,613	(10,096)	$ 813,431
Balance (in shares) at Dec. 31, 2020	26,776,796				26,776,796
Balance at Dec. 31, 2020	$ 27	284,848	362,901	(3,420)	$ 644,356
Net income					21,462
Other comprehensive loss
Comprehensive income					11,424
Net income					$ 21,462
Balance (in shares) at Dec. 31, 2020	26,776,796				26,776,796
Balance at Dec. 31, 2020	$ 27	284,848	362,901	(3,420)	$ 644,356
Balance (in shares) at Sep. 30, 2021	27,603,649				27,603,649
Balance at Sep. 30, 2021	$ 28	464,900	373,151	(13,458)	$ 824,621
Balance (in shares) at Mar. 31, 2021	27,689,746
Balance at Mar. 31, 2021	$ 28	456,886	366,613	(10,096)	813,431
Common shares issued on exercise of options and other, net of shares withheld for tax obligations (in shares)	85,317
Common shares issued on exercise of options and other, net of shares withheld for tax obligations		(81)			(81)
Stock-based compensation expense		4,941			4,941
Net income			12,915		12,915
Other comprehensive loss
Foreign currency translation adjustment				2,030	2,030
Net unrealized gains (losses) on investments in securities				(49)	(49)
Comprehensive income					14,896
Common shares issued on exercise of options and other, net of shares withheld for tax obligations (in shares)	85,317
Common shares issued on exercise of options and other, net of shares withheld for tax obligations		(81)			(81)
Stock-based compensation expense		4,941			4,941
Repurchases of common stock (in shares)	(14,000)
Repurchases of common stock		(149)	(1,061)		(1,210)
Net income			12,915		12,915
Foreign currency translation adjustment				2,030	2,030
Balance (in shares) at Mar. 31, 2021	27,689,746
Balance at Mar. 31, 2021	$ 28	456,886	366,613	(10,096)	813,431
Balance (in shares) at Jun. 30, 2021	27,761,063
Balance at Jun. 30, 2021	$ 28	461,597	378,467	(8,115)	831,977
Stock-based compensation expense		4,978			4,978
Net income			4,835		4,835
Other comprehensive loss
Foreign currency translation adjustment				(5,298)	(5,298)
Net unrealized gains (losses) on investments in securities				(45)	(45)
Comprehensive income					(508)
Stock-based compensation expense		4,978			4,978
Repurchases of common stock (in shares)	(157,414)
Repurchases of common stock		(1,675)	(10,151)		(11,826)
Net income			4,835		4,835
Foreign currency translation adjustment				(5,298)	(5,298)
Balance (in shares) at Jun. 30, 2021	27,761,063
Balance at Jun. 30, 2021	$ 28	461,597	378,467	(8,115)	$ 831,977
Balance (in shares) at Sep. 30, 2021	27,603,649				27,603,649
Balance at Sep. 30, 2021	$ 28	$ 464,900	$ 373,151	$ (13,458)	$ 824,621