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, 2017	$ 605,726	$ 16	$ 2	$ 559,918	$ (475,184)	$ (5,659)	$ 526,633
Beginning Balance (in shares) at Dec. 31, 2017		15,817	2,035		(6,405)
Net income (loss)	1,673	$ 0	$ 0	0	$ 0	0	1,673
Other comprehensive income (loss)	1,440	0	0	0	0	1,440	0
Share-based compensation expense	4,743	0	0	4,743	0	0	0
Ending Balance at Mar. 31, 2018	613,582	$ 16	$ 2	564,661	$ (475,184)	(4,219)	528,306
Ending Balance (in shares) at Mar. 31, 2018		15,817	2,035		(6,405)
Beginning Balance at Dec. 31, 2017	605,726	$ 16	$ 2	559,918	$ (475,184)	(5,659)	526,633
Beginning Balance (in shares) at Dec. 31, 2017		15,817	2,035		(6,405)
Net income (loss)	6,501
Other comprehensive income (loss)	(2,452)
Ending Balance at Jun. 30, 2018	620,359	$ 16	$ 2	570,502	$ (475,184)	(8,111)	533,134
Ending Balance (in shares) at Jun. 30, 2018		15,837	2,035		(6,405)
Beginning Balance at Mar. 31, 2018	613,582	$ 16	$ 2	564,661	$ (475,184)	(4,219)	528,306
Beginning Balance (in shares) at Mar. 31, 2018		15,817	2,035		(6,405)
Net income (loss)	4,828	$ 0	$ 0	0	$ 0	0	4,828
Other comprehensive income (loss)	(3,892)	0	0	0	0	(3,892)	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
Share-based compensation expense	3,370	$ 0	$ 0	3,370	$ 0	0	0
Ending Balance at Jun. 30, 2018	620,359	$ 16	$ 2	570,502	$ (475,184)	(8,111)	533,134
Ending Balance (in shares) at Jun. 30, 2018		15,837	2,035		(6,405)
Net income (loss)	12,699	$ 0	$ 0	0	$ 0	0	12,699
Other comprehensive income (loss)	(607)	0	0	0	0	(607)	0
Share-based compensation expense	2,972	0	0	2,972	0	0	0
Ending Balance at Sep. 30, 2018	635,423	$ 16	$ 2	573,474	$ (475,184)	(8,718)	545,833
Ending Balance (in shares) at Sep. 30, 2018		15,837	2,035		(6,405)
Net income (loss)	3,301	$ 0	$ 0	0	$ 0	0	3,301
Other comprehensive income (loss)	(1,499)	0	0	0	0	(1,499)	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	3,483	$ 0	$ 0	3,483	$ 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 (loss)	(7,906)	$ 0	$ 0	0	$ 0	0	(7,906)
Other comprehensive income (loss)	253	0	0	0	0	253	0
Issuance of class A common stock under stock option plans	1,507	$ 0	$ 0	1,507	$ 0	0	0
Issuance of class A common stock under stock option plans (in shares)		13	0		0
Purchases of treasury stock	(48,244)	$ 0	$ 0	0	$ (48,244)	0	0
Purchases of treasury stock (in shares)		0	0		(363)
Share-based compensation expense	2,965	$ 0	$ 0	2,965	$ 0	0	0
Ending Balance at Mar. 31, 2019	478,306	$ 16	$ 2	581,429	$ (634,405)	(9,964)	541,228
Ending Balance (in shares) at Mar. 31, 2019		15,850	2,035		(7,648)
Beginning Balance at Dec. 31, 2018	529,731	$ 16	$ 2	576,957	$ (586,161)	(10,217)	549,134
Beginning Balance (in shares) at Dec. 31, 2018		15,837	2,035		(7,285)
Net income (loss)	12,488
Other comprehensive income (loss)	907
Ending Balance at Jun. 30, 2019	502,689	$ 16	$ 2	584,764	$ (634,405)	(9,310)	561,622
Ending Balance (in shares) at Jun. 30, 2019		15,853	2,035		(7,648)
Beginning Balance at Mar. 31, 2019	478,306	$ 16	$ 2	581,429	$ (634,405)	(9,964)	541,228
Beginning Balance (in shares) at Mar. 31, 2019		15,850	2,035		(7,648)
Net income (loss)	20,394	$ 0	$ 0	0	$ 0	0	20,394
Other comprehensive income (loss)	654	0	0	0	0	654	0
Issuance of class A common stock under stock option plans	329	$ 0	0	329	0	0	0
Issuance of class A common stock under stock option plans (in shares)		3
Share-based compensation expense	3,006	$ 0	0	3,006	0	0	0
Ending Balance at Jun. 30, 2019	$ 502,689	$ 16	$ 2	$ 584,764	$ (634,405)	$ (9,310)	$ 561,622
Ending Balance (in shares) at Jun. 30, 2019		15,853	2,035		(7,648)

Amount of increase to additional paid-in capital (APIC) from recognition of equity-based compensation.

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