CONDENSED CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - UNAUDITED - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Additional Paid-in Capital Adjustments due to adoption of new accounting standards	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Accumulated Earnings	Accumulated Earnings Adjustments due to adoption of new accounting standards	Noncontrolling Interest
Balance, beginning of period, shares at Dec. 31, 2021		32,495,000
Balance, beginning of period at Dec. 31, 2021	$ 440,244	$ 705	$ 488,303		$ (930,106)	$ (38,353)	$ 916,060		$ 3,635
Net income							6,113
Unrealized gain (loss) on short-term investments, net of tax						(2)
Foreign currency translation adjustments						(1,182)
Total comprehensive income (loss)	4,929
Repurchase of common stock	(23,801)	$ (1)	(7,804)		(15,996)
Repurchase of common stock, shares		(389,000)
Issuance of common stock pursuant to employee stock purchase plan	650		650
Issuance of common stock pursuant to employee stock purchase plan, shares		12,000
Issuance of restricted common stock pursuant to stock-based compensation plans		$ 5	(5)
Issuance of restricted common stock pursuant to stock-based compensation plans, shares		476,000
Cancellation of restricted common stock issued pursuant to stock-based compensation plans, shares		(34,000)
Stock-based compensation expense	5,581		5,581
Settlement of convertible debt securities, net of tax	(4,845)		(4,845)
Dividends	(8,586)						(8,586)
Balance, ending of period, shares at Mar. 31, 2022		32,560,000
Balance, ending of period at Mar. 31, 2022	414,172	$ 709	472,078	$ (9,802)	(946,102)	(39,537)	923,389	$ 9,802	3,635
Balance, beginning of period, shares at Dec. 31, 2021		32,495,000
Balance, beginning of period at Dec. 31, 2021	440,244	$ 705	488,303		(930,106)	(38,353)	916,060		3,635
Net income	11,430
Unrealized gain (loss) on short-term investments, net of tax	3
Foreign currency translation adjustments	(17,182)
Total comprehensive income (loss)	(5,749)
Balance, ending of period, shares at Jun. 30, 2022		32,195
Balance, ending of period at Jun. 30, 2022	377,022	$ 709	479,271		(967,659)	(55,532)	920,233
Balance, beginning of period, shares at Mar. 31, 2022		32,560,000
Balance, beginning of period at Mar. 31, 2022	414,172	$ 709	472,078	$ (9,802)	(946,102)	(39,537)	923,389	$ 9,802	3,635
Net income	5,317						5,317
Unrealized gain (loss) on short-term investments, net of tax	5					(5)
Foreign currency translation adjustments	(16,000)					(16,000)
Total comprehensive income (loss)	(10,678)
Repurchase of common stock	21,673		(116)		(21,557)
Repurchase of common stock, shares		(362,000)
Issuance of common stock pursuant to employee stock purchase plan	773		773
Issuance of common stock pursuant to employee stock purchase plan, shares		15,000
Issuance of restricted common stock pursuant to stock-based compensation plans		$ 1	(1)
Issuance of restricted common stock pursuant to stock-based compensation plans, shares		42,000
Cancellation of restricted common stock issued pursuant to stock-based compensation plans		$ (1)	1
Cancellation of restricted common stock issued pursuant to stock-based compensation plans, shares		(60,000)
Stock-based compensation expense	6,536		6,536
Dividends	(8,473)						(8,473)
Write-off of noncontrolling interest	(3,635)								$ (3,635)
Balance, ending of period, shares at Jun. 30, 2022		32,195
Balance, ending of period at Jun. 30, 2022	$ 377,022	$ 709	479,271		(967,659)	(55,532)	920,233
Balance, beginning of period, shares at Dec. 31, 2022	31,269,000	31,269
Balance, beginning of period at Dec. 31, 2022	$ 355,249	$ 708	495,189		(1,018,034)	(58,829)	936,215
Net income							20,928
Foreign currency translation adjustments						2,843
Total comprehensive income (loss)	23,771
Repurchase of common stock	(9,306)	$ (2)	(9,304)
Repurchase of common stock, shares		(166)
Issuance of common stock pursuant to employee stock purchase plan	893		893
Issuance of common stock pursuant to employee stock purchase plan, shares		19
Issuance of restricted common stock pursuant to stock-based compensation plans		$ 6	(6)
Issuance of restricted common stock pursuant to stock-based compensation plans, shares		574
Cancellation of restricted common stock issued pursuant to stock-based compensation plans, shares		(18,000)
Stock-based compensation expense	6,412		6,412
Dividends	(8,796)						(8,796)
Balance, ending of period, shares at Mar. 31, 2023		31,678,000
Balance, ending of period at Mar. 31, 2023	$ 368,223	$ 712	493,184		(1,018,034)	55,986	948,347
Balance, beginning of period, shares at Dec. 31, 2022	31,269,000	31,269
Balance, beginning of period at Dec. 31, 2022	$ 355,249	$ 708	495,189		(1,018,034)	(58,829)	936,215
Net income	34,882
Unrealized gain (loss) on short-term investments, net of tax	0
Foreign currency translation adjustments	4,552
Total comprehensive income (loss)	$ 39,434
Balance, ending of period, shares at Jun. 30, 2023	31,751,000	31,751
Balance, ending of period at Jun. 30, 2023	$ 383,311	$ 713	501,486		(1,018,034)	(54,277)	953,423
Balance, beginning of period, shares at Mar. 31, 2023		31,678,000
Balance, beginning of period at Mar. 31, 2023	368,223	$ 712	493,184		(1,018,034)	55,986	948,347
Net income	13,954						13,954
Unrealized gain (loss) on short-term investments, net of tax	0
Foreign currency translation adjustments	1,709					1,709
Total comprehensive income (loss)	15,663
Repurchase of common stock	(112)		(112)
Repurchase of common stock, shares		(2)
Issuance of common stock pursuant to employee stock purchase plan	771		771
Issuance of common stock pursuant to employee stock purchase plan, shares		18
Issuance of restricted common stock pursuant to stock-based compensation plans		$ 1	(1)
Issuance of restricted common stock pursuant to stock-based compensation plans, shares		64
Cancellation of restricted common stock issued pursuant to stock-based compensation plans, shares		(7,000)
Stock-based compensation expense	7,644		7,644
Dividends	$ (8,878)						(8,878)
Balance, ending of period, shares at Jun. 30, 2023	31,751,000	31,751
Balance, ending of period at Jun. 30, 2023	$ 383,311	$ 713	$ 501,486		$ (1,018,034)	$ (54,277)	$ 953,423