CONSOLIDATED STATEMENTS OF STOCKHOLDERS' EQUITY (UNAUDITED) - USD ($) shares in Thousands, $ in Thousands	Common Stock Class A Common shares	Common Stock Class B Common shares	Common Stock	Additional Paid In Capital	Retained Earnings Class A Common shares	Retained Earnings Class B Common shares	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Class A Common shares	Class B Common shares	Total
Balance at beginning of period at Dec. 31, 2022			$ 4,648	$ 141,694			$ 742,250	$ (31,979)			$ 856,613
Balance (in shares) at Dec. 31, 2022	17,585	2,160
Increase (Decrease) in Stockholders' Equity
Net income							70,715				70,715
Net change in AOCI								1,378			1,378
Dividends declared on Common Stock:
Dividends declared on Common Stock					$ (19,566)	$ (2,201)			$ (19,566)	$ (2,201)
Stock options exercised, net of shares withheld			(1)	(193)							(194)
Conversion of Class B to Class A Common Shares (in shares)	3	(3)
Repurchase of Class A Common Stock			(80)	(2,640)			(13,390)				(16,110)
Repurchase of Class A Common Stock (in shares)	(363)
Deferred director compensation expense - Class A Common Stock				349							349
Deferred designed key employee compensation expense - Class A Common Stock				495							495
Deferred designed key employee compensation expense - Class A Common Stock (In shares)	7
Employee stock purchase plan - Class A Common Stock			3	535							538
Employee stock purchase plan - Class A Common Stock (in shares)	13
Stock-based awards, Restricted stock, net of shares withheld			2	798							800
Stock-based awards, Restricted stock, net of shares withheld (in shares)	51
Stock-based awards, Stock options				583							583
Balance at end of period at Sep. 30, 2023			4,572	141,621			777,808	(30,601)			893,400
Balance (in shares) at Sep. 30, 2023	17,296	2,157
Balance at beginning of period at Jun. 30, 2023			4,617	142,462			771,260	(31,368)			886,971
Balance (in shares) at Jun. 30, 2023	17,449	2,157
Increase (Decrease) in Stockholders' Equity
Net income							21,571				21,571
Net change in AOCI								767			767
Dividends declared on Common Stock:
Dividends declared on Common Stock					(6,448)	(734)			(6,448)	(734)
Stock options exercised, net of shares withheld				(10)							(10)
Repurchase of Class A Common Stock			(46)	(1,509)			(7,841)				(9,396)
Repurchase of Class A Common Stock (in shares)	(206)
Deferred director compensation expense - Class A Common Stock				123							123
Deferred designed key employee compensation expense - Class A Common Stock				36							36
Employee stock purchase plan - Class A Common Stock			1	172							173
Employee stock purchase plan - Class A Common Stock (in shares)	4
Stock-based awards, Restricted stock, net of shares withheld				172							172
Stock-based awards, Restricted stock, net of shares withheld (in shares)	49
Stock-based awards, Stock options				175							175
Balance at end of period at Sep. 30, 2023			4,572	141,621			777,808	(30,601)			893,400
Balance (in shares) at Sep. 30, 2023	17,296	2,157
Balance at beginning of period at Dec. 31, 2023			4,553	142,124			786,487	(20,408)			912,756
Balance (in shares) at Dec. 31, 2023	17,203	2,155
Increase (Decrease) in Stockholders' Equity
Net income							82,355				82,355
Net change in AOCI								6,175			6,175
Dividends declared on Common Stock:
Dividends declared on Common Stock					(20,989)	(2,388)			(20,989)	(2,388)
Stock options exercised, net of shares withheld			32	1,784			(2,510)				(694)
Stock options exercised, net of shares withheld (in shares)	65
Conversion of Class B to Class A Common Shares (in shares)	5	(5)
Net change in notes receivable on Class A Common Stock				106							106
Deferred director compensation expense - Class A Common Stock				620							620
Deferred designed key employee compensation expense - Class A Common Stock				560							560
Deferred designed key employee compensation expense - Class A Common Stock (In shares)	11
Employee stock purchase plan - Class A Common Stock			3	573							576
Employee stock purchase plan - Class A Common Stock (in shares)	10
Stock-based awards, Performance stock units				108							108
Stock-based awards, Restricted stock, net of shares withheld			(3)	507			(440)				64
Stock-based awards, Restricted stock, net of shares withheld (in shares)	(1)
Stock-based awards, Stock options				456							456
Balance at end of period at Sep. 30, 2024			4,585	146,838			842,515	(14,233)			979,705
Balance (in shares) at Sep. 30, 2024	17,293	2,150
Balance at beginning of period at Jun. 30, 2024			4,581	144,139			825,496	(18,793)			955,423
Balance (in shares) at Jun. 30, 2024	17,275	2,150
Increase (Decrease) in Stockholders' Equity
Net income							26,543				26,543
Net change in AOCI								4,560			4,560
Dividends declared on Common Stock:
Dividends declared on Common Stock					$ (7,007)	$ (796)			$ (7,007)	$ (796)
Stock options exercised, net of shares withheld			4	1,767			(1,601)				170
Stock options exercised, net of shares withheld (in shares)	17
Net change in notes receivable on Class A Common Stock				60							60
Deferred director compensation expense - Class A Common Stock				109							109
Deferred designed key employee compensation expense - Class A Common Stock				164							164
Employee stock purchase plan - Class A Common Stock			1	177							178
Employee stock purchase plan - Class A Common Stock (in shares)	3
Stock-based awards, Performance stock units				36							36
Stock-based awards, Restricted stock, net of shares withheld			(1)	262			(120)				141
Stock-based awards, Restricted stock, net of shares withheld (in shares)	(2)
Stock-based awards, Stock options				124							124
Balance at end of period at Sep. 30, 2024			$ 4,585	$ 146,838			$ 842,515	$ (14,233)			$ 979,705
Balance (in shares) at Sep. 30, 2024	17,293	2,150