CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Total	Class A	Class B Convertible	Additional Paid-in Capital	Treasury Stock	Accumulated Other Comprehensive Income (Loss)	Retained Earnings
Beginning Balance at Dec. 31, 2016	$ 566,317	$ 16	$ 2	$ 543,974	$ (475,184)	$ (10,929)	$ 508,438
Beginning Balance (in shares) at Dec. 31, 2016		15,805	2,035		(6,405)
Net income	18,195	$ 0	$ 0	0	$ 0	0	18,195
Other comprehensive income (loss)	5,270	0	0	0	0	5,270	0
Issuance of class A common stock under stock option plans	1,677	$ 0	$ 0	1,677	$ 0	0	0
Issuance of class A common stock under stock option plans (in shares)		12	0		0
Share-based compensation expense	14,267	$ 0	$ 0	14,267	$ 0	0	0
Ending Balance at Dec. 31, 2017	605,726	$ 16	$ 2	559,918	$ (475,184)	(5,659)	526,633
Ending Balance (in shares) at Dec. 31, 2017		15,817	2,035		(6,405)
Net income	22,501	$ 0	$ 0	0	$ 0	0	22,501
Other comprehensive income (loss)	(4,558)	0	0	0	0	(4,558)	0
Issuance of class A common stock under stock option plans	2,471	$ 0	$ 0	2,471	$ 0	0	0
Issuance of class A common stock under stock option plans (in shares)		20	0		0
Purchases of treasury stock	(110,977)	$ 0	$ 0	0	$ (110,977)	0	0
Purchases of treasury stock (in shares)		0	0		(880)
Share-based compensation expense	14,568	$ 0	$ 0	14,568	$ 0	0	0
Ending Balance at Dec. 31, 2018	529,731	$ 16	$ 2	576,957	$ (586,161)	(10,217)	549,134
Ending Balance (in shares) at Dec. 31, 2018		15,837	2,035		(7,285)
Net income	34,355	$ 0	$ 0	0	$ 0	0	34,355
Other comprehensive income (loss)	566	0	0	0	0	566	0
Issuance of class A common stock under stock option plans	6,569	$ 0	$ 0	6,569	$ 0	0	0
Issuance of class A common stock under stock option plans (in shares)		51	0		0
Purchases of treasury stock	(72,719)	$ 0	$ 0	0	$ (72,719)	0	0
Purchases of treasury stock (in shares)		0	0		(522)
Share-based compensation expense	10,057	$ 0	$ 0	10,057	$ 0	0	0
Ending Balance at Dec. 31, 2019	$ 508,559	$ 16	$ 2	$ 593,583	$ (658,880)	$ (9,651)	$ 583,489
Ending Balance (in shares) at Dec. 31, 2019		15,888	2,035		(7,807)

Amount of increase to additional paid-in capital (APIC) for recognition of cost for award under share-based payment arrangement.

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