Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) $ in Thousands	Common Stock [Member] Class A [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings [Member]	Total
Balance at beginning of period at Dec. 31, 2021	$ 91	$ 601,703	$ (1,526,860)	$ (73,896)	$ 1,911,734	$ 912,772
Stockholders' Equity [Roll Forward]
Net income	0	0	0	0	38,716	38,716
Other comprehensive income (loss), net of tax	0	0	0	4,368	0	4,368
Repurchase of Class A common stock (Note 6)	0	0	(10,006)	0	0	(10,006)
Exercise of employee stock options/vesting of stock awards	0	(6,572)	10,088	0	0	3,516
Stock-based compensation	0	4,127	0	0	0	4,127
Cash dividends	0	0	0	0	(19,293)	(19,293)
Balance at end of period at Mar. 31, 2022	91	599,258	(1,526,778)	(69,528)	1,931,157	934,200
Balance at beginning of period at Dec. 31, 2022	91	613,278	(1,569,061)	(86,509)	1,939,497	897,296
Stockholders' Equity [Roll Forward]
Net income	0	0	0	0	11,376	11,376
Other comprehensive income (loss), net of tax	0	0	0	(4,496)	0	(4,496)
Repurchase of Class A common stock (Note 6)	0	0	0	0	0	0
Exercise of employee stock options/vesting of stock awards	0	(5,797)	9,981	0	0	4,184
Stock-based compensation	0	4,002	0	0	0	4,002
Cash dividends	0	0	0	0	(19,392)	(19,392)
Balance at end of period at Mar. 31, 2023	$ 91	$ 611,483	$ (1,559,080)	$ (91,005)	$ 1,931,481	$ 892,970