Note J - Business Segments and Foreign Operations - Segment Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Net Sales	$ 240,733	$ 168,182	$ 166,282
Intra-segment sales	31,655	20,442	19,330
Inter-segment sales	28,683	25,671	29,552
Interest income	55	72	147
Interest expense	282	303	426
Income taxes	4,773	(3,414)	(12,282)
Depreciation and amortization	6,464	7,017	8,847
Net income attributable to Twin Disc	9,528	(6,294)	(13,104)
Assets	234,713	210,898	213,922
Expenditures for segment assets	6,328	3,133	4,214
Manufacturing Segment [Member]
Intra-segment sales	22,912	13,146	11,476
Inter-segment sales	26,074	22,921	26,883
Distribution Segment [Member]
Intra-segment sales	8,743	7,296	7,854
Inter-segment sales	2,609	2,750	2,669
Operating Segments [Member]
Net Sales	301,071	214,295	215,164
Interest income	34	74	142
Interest expense	275	301	398
Income taxes	16,370	2,468	(2,446)
Depreciation and amortization	6,084	6,550	8,007
Net income attributable to Twin Disc	23,866	3,067	(11,932)
Assets	312,120	272,554	274,309
Expenditures for segment assets	5,730	2,964	4,038
Operating Segments [Member] | Manufacturing Segment [Member]
Net Sales	216,383	146,491	140,965
Interest income	16	42	117
Interest expense	275	301	397
Income taxes	15,782	1,684	(2,554)
Depreciation and amortization	5,632	6,125	7,536
Net income attributable to Twin Disc	22,799	629	(12,694)
Assets	265,260	222,136	221,590
Expenditures for segment assets	5,482	2,674	3,850
Operating Segments [Member] | Distribution Segment [Member]
Net Sales	84,688	67,804	74,199
Interest income	18	32	25
Interest expense			1
Income taxes	588	784	108
Depreciation and amortization	452	425	471
Net income attributable to Twin Disc	1,067	2,438	762
Assets	46,860	50,418	52,719
Expenditures for segment assets	$ 248	$ 290	$ 188