Consolidated Statements of Shareholders' Equity - USD ($) $ in Thousands	Total	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Class A Common Stock Common Stock	Class B Common Stock Common Stock
Shareholders' Equity at beginning of period at Jun. 30, 2018	$ 193,024	$ 1,881	$ 249,945	$ 1,816	$ (62,769)	$ 13	$ 2,138
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income	39,344		39,344
Other comprehensive income (loss)	121			121
Issuance of non-restricted stock (42,000 shares in 2019, 34,000 shares in 2020, 45,000 shares in 2021)	(11)	(563)			552
Conversion of Class A to Class B common stock (13,000 shares in 2019, 58,000 shares in 2020, 5,000 shares in 2021)	0					(1)	1
Compensation expense related to stock incentive plans	6,617	6,617
Performance share issuance (81,000 shares in 2019, 67,000 shares in 2020)	(656)	(1,717)			1,061
Restricted share units issuance (106,000 shares in 2019, 99,000 shares in 2020, 163,000 shares in 2021)	(746)	(2,125)			1,379
Relative total shareholder return performance units issuance (27,000 shares in 2019, 48,000 shares in 2020, 32,000 shares in 2021)	(173)	(523)			350
Repurchase of Common Stock (67,000 shares in 2019, 146,000 shares in 2020, 278,000 shares in 2021)	(9,132)				(9,132)
Dividends declared ($0.32 per share in 2019, $0.36 per share in 2020, $0.36 per share in 2021)	(11,898)		(11,898)
Shareholders' Equity at end of period at Jun. 30, 2019	216,490	3,570	277,391	1,937	(68,559)	12	2,139
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income	41,054		41,054
Other comprehensive income (loss)	200			200
Issuance of non-restricted stock (42,000 shares in 2019, 34,000 shares in 2020, 45,000 shares in 2021)	0	(440)			440
Conversion of Class A to Class B common stock (13,000 shares in 2019, 58,000 shares in 2020, 5,000 shares in 2021)	0	(21)			21	(2)	2
Compensation expense related to stock incentive plans	5,454	5,454
Performance share issuance (81,000 shares in 2019, 67,000 shares in 2020)	(512)	(1,391)			879
Restricted share units issuance (106,000 shares in 2019, 99,000 shares in 2020, 163,000 shares in 2021)	(455)	(1,768)			1,313
Relative total shareholder return performance units issuance (27,000 shares in 2019, 48,000 shares in 2020, 32,000 shares in 2021)	(330)	(954)			624
Reclassification of equity-classified awards	(680)	(680)
Repurchase of Common Stock (67,000 shares in 2019, 146,000 shares in 2020, 278,000 shares in 2021)	(3,004)				(3,004)
Dividends declared ($0.32 per share in 2019, $0.36 per share in 2020, $0.36 per share in 2021)	(13,421)		(13,421)
Shareholders' Equity at end of period at Jun. 30, 2020	244,796	3,770	305,024	2,137	(68,286)	10	2,141
Increase (Decrease) in Shareholders' Equity [Roll Forward]
Net income	7,416		7,416
Other comprehensive income (loss)	(157)			(157)
Issuance of non-restricted stock (42,000 shares in 2019, 34,000 shares in 2020, 45,000 shares in 2021)	(23)	(617)			594
Conversion of Class A to Class B common stock (13,000 shares in 2019, 58,000 shares in 2020, 5,000 shares in 2021)	0					(1)	1
Compensation expense related to stock incentive plans	5,676	5,676
Restricted share units issuance (106,000 shares in 2019, 99,000 shares in 2020, 163,000 shares in 2021)	(805)	(2,945)			2,140
Relative total shareholder return performance units issuance (27,000 shares in 2019, 48,000 shares in 2020, 32,000 shares in 2021)	(156)	(586)			430
Reclassification of equity-classified awards	134		134
Repurchase of Common Stock (67,000 shares in 2019, 146,000 shares in 2020, 278,000 shares in 2021)	(3,671)				(3,671)
Dividends declared ($0.32 per share in 2019, $0.36 per share in 2020, $0.36 per share in 2021)	(13,540)		(13,540)
Shareholders' Equity at end of period at Jun. 30, 2021	$ 239,670	$ 5,298	$ 299,034	$ 1,980	$ (68,793)	$ 9	$ 2,142