Consolidated Statements of Stockholders' Equity - USD ($) $ in Thousands	Total	Common Stock Outstanding Class A	Common Stock Outstanding Class B	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss
Beginning balance at Jun. 30, 2019	$ 83,379	$ 6,207	$ 690	$ 55,276	$ 80,487	$ (59,281)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	(2,981)				778	(3,759)
Repurchase of shares	(10)		(2)	(8)
Stock-based compensation	214	57		157
Conversion		6	(6)
Ending balance at Sep. 30, 2019	80,602	6,270	682	55,425	81,265	(63,040)
Beginning balance at Jun. 30, 2019	83,379	6,207	690	55,276	80,487	(59,281)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	930
Ending balance at Dec. 31, 2019	84,619	6,280	681	55,522	82,525	(60,389)
Beginning balance at Sep. 30, 2019	80,602	6,270	682	55,425	81,265	(63,040)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	3,911				1,260	2,651
Repurchase of shares	(921)			(3)
Issuance of stock	37		7	30
Stock-based compensation	72	2		70
Conversion		8	(8)
Ending balance at Dec. 31, 2019	84,619	6,280	681	55,522	82,525	(60,389)
Accumulated balance consists of:
Translation loss						(50,624)
Pension and postretirement plans, net of taxes						(9,765)
Accumulated other comprehensive loss						(60,389)
Accumulated other comprehensive loss	(75,415)
Beginning balance at Jun. 30, 2020	45,983	6,308	680	55,762	58,648	(75,415)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	3,858				4,116	(258)
Repurchase of shares	(6)		(2)	(4)
Stock-based compensation	367	8		359
Conversion		26	(26)
Ending balance at Sep. 30, 2020	50,202	6,342	652	56,117	62,764	(75,673)
Beginning balance at Jun. 30, 2020	45,983	6,308	680	55,762	58,648	(75,415)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	11,562
Ending balance at Dec. 31, 2020	58,084	6,448	657	56,184	66,621	(71,826)
Beginning balance at Sep. 30, 2020	50,202	6,342	652	56,117	62,764	(75,673)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Total comprehensive income (loss)	7,704				3,857	3,847
Repurchase of shares	(1)			(1)
Issuance of stock	25		8	17
Stock-based compensation	154	103		51
Conversion		3	(3)
Ending balance at Dec. 31, 2020	58,084	$ 6,448	$ 657	$ 56,184	$ 66,621	(71,826)
Accumulated balance consists of:
Translation loss						(58,264)
Pension and postretirement plans, net of taxes						(13,562)
Accumulated other comprehensive loss	$ (71,826)					$ (71,826)