BUSINESS SEGMENTS AND FOREIGN OPERATIONS (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2010
BUSINESS SEGMENTS AND FOREIGN OPERATIONS [Abstract]
Number of reportable segments	2
Segment Reporting Information [Line Items]
Net sales	$ 355,870	$ 310,393	$ 227,534
Interest income	95	98	84
Interest expense	1,475	1,719	2,282
Income taxes	18,446	13,064	992
Depreciation and amortization	10,756	9,904	9,817
Net earnings	26,112	18,830	597
Assets	303,832	309,120
Net sales [Abstract]
Total consolidated net sales	355,870	310,393	227,534
Net earnings attributable to Twin Disc [Abstract]
Other corporate expenses	(10,025)	(13,912)	(4,882)
Total consolidated net earnings attributable to Twin Disc	26,112	18,830	597
Assets [Abstract]
Total consolidated assets	303,832	309,120
Other significant items [Abstract]
Interest income	95	98	84
Interest expense	1,475	1,719	2,282
Income taxes	18,446	13,064	992
Depreciation and amortization	10,756	9,904	9,817
Expenditures for segment assets	13,733	12,028	4,456
Net sales
Total	355,870	310,393	227,534
Long-lived assets
Total	74,224	73,162
Revenue, Major Customer [Line Items]
Percentage of revenue generated from a single customer (in hundredths)	10.00%
United States [Member]
Segment Reporting Information [Line Items]
Net sales	165,658	127,469	79,301
Net sales [Abstract]
Total consolidated net sales	165,658	127,469	79,301
Net sales
Total	165,658	127,469	79,301
Long-lived assets
Total	53,083	48,077
Belgium [Member]
Long-lived assets
Total	7,372	8,761
Canada [Member]
Segment Reporting Information [Line Items]
Net sales	44,889	44,659	13,600
Net sales [Abstract]
Total consolidated net sales	44,889	44,659	13,600
Net sales
Total	44,889	44,659	13,600
Switzerland [Member]
Long-lived assets
Total	8,278	9,574
Italy [Member]
Segment Reporting Information [Line Items]
Net sales	27,075	32,063	30,244
Net sales [Abstract]
Total consolidated net sales	27,075	32,063	30,244
Net sales
Total	27,075	32,063	30,244
Long-lived assets
Total	4,438	6,137
Other countries [Member]
Segment Reporting Information [Line Items]
Net sales	118,248	106,202	104,389
Net sales [Abstract]
Total consolidated net sales	118,248	106,202	104,389
Net sales
Total	118,248	106,202	104,389
Long-lived assets
Total	1,053	613
Elimination of inter-company sales [Member]
Segment Reporting Information [Line Items]
Net sales	(98,715)	(85,796)	(57,172)
Net sales [Abstract]
Total consolidated net sales	(98,715)	(85,796)	(57,172)
Net sales
Total	(98,715)	(85,796)	(57,172)
Manufacturing [Member]
Segment Reporting Information [Line Items]
Net sales	325,174	267,630	183,369
Interest expense	3,798	4,168	4,795
Income taxes	20,075	18,565	1,475
Depreciation and amortization	8,373	7,605	7,537
Net earnings	28,941	25,983	400
Assets	272,098	271,454	217,656
Expenditures for segment assets			3,714
Net sales [Abstract]
Total consolidated net sales	325,174	267,630	183,369
Net earnings attributable to Twin Disc [Abstract]
Total consolidated net earnings attributable to Twin Disc	28,941	25,983	400
Assets [Abstract]
Total consolidated assets	272,098	271,454	217,656
Other significant items [Abstract]
Interest income	688	856	979
Interest expense	3,798	4,168	4,795
Income taxes	20,075	18,565	1,475
Depreciation and amortization	8,373	7,605	7,537
Expenditures for segment assets	11,821	11,293
Net sales
Total	325,174	267,630	183,369
Manufacturing [Member] | Intra-segment sales [Member]
Segment Reporting Information [Line Items]
Net sales	16,189	12,712	10,752
Net sales [Abstract]
Total consolidated net sales	16,189	12,712	10,752
Net sales
Total	16,189	12,712	10,752
Manufacturing [Member] | Inter-segment sales [Member]
Segment Reporting Information [Line Items]
Net sales	71,134	56,159	29,715
Net sales [Abstract]
Total consolidated net sales	71,134	56,159	29,715
Net sales
Total	71,134	56,159	29,715
Distribution [Member]
Segment Reporting Information [Line Items]
Net sales	129,411	128,559	101,337
Interest expense	64	66	75
Income taxes	2,460	3,233	2,412
Depreciation and amortization	871	834	873
Net earnings	7,196	6,759	5,079
Assets	58,275	54,028	53,514
Expenditures for segment assets			234
Net sales [Abstract]
Total consolidated net sales	129,411	128,559	101,337
Net earnings attributable to Twin Disc [Abstract]
Total consolidated net earnings attributable to Twin Disc	7,196	6,759	5,079
Assets [Abstract]
Total consolidated assets	58,275	54,028	53,514
Other significant items [Abstract]
Interest income	39	34	21
Interest expense	64	66	75
Income taxes	2,460	3,233	2,412
Depreciation and amortization	871	834	873
Expenditures for segment assets	1,158	334
Net sales
Total	129,411	128,559	101,337
Distribution [Member] | Intra-segment sales [Member]
Segment Reporting Information [Line Items]
Net sales	7,672	13,289	12,990
Net sales [Abstract]
Total consolidated net sales	7,672	13,289	12,990
Net sales
Total	7,672	13,289	12,990
Distribution [Member] | Inter-segment sales [Member]
Segment Reporting Information [Line Items]
Net sales	3,720	3,636	3,715
Net sales [Abstract]
Total consolidated net sales	3,720	3,636	3,715
Net sales
Total	3,720	3,636	3,715
Corporate Assets [Member]
Segment Reporting Information [Line Items]
Assets	(26,541)	(16,362)
Assets [Abstract]
Total consolidated assets	(26,541)	(16,362)
Reportable Segment [Member]
Segment Reporting Information [Line Items]
Net sales	454,585	396,189	284,706
Interest expense	3,862	4,234	4,870
Income taxes	22,535	21,798	3,887
Depreciation and amortization	9,244	8,439	8,410
Net earnings	36,137	32,742	5,479
Assets	330,373	325,482	271,170
Expenditures for segment assets			3,948
Net sales [Abstract]
Total consolidated net sales	454,585	396,189	284,706
Net earnings attributable to Twin Disc [Abstract]
Total consolidated net earnings attributable to Twin Disc	36,137	32,742	5,479
Assets [Abstract]
Total consolidated assets	330,373	325,482	271,170
Other significant items [Abstract]
Interest income	727	890	1,000
Interest expense	3,862	4,234	4,870
Income taxes	22,535	21,798	3,887
Depreciation and amortization	9,244	8,439	8,410
Expenditures for segment assets	12,979	11,627	3,948
Net sales
Total	454,585	396,189	284,706
Reportable Segment [Member] | Intra-segment sales [Member]
Segment Reporting Information [Line Items]
Net sales	23,861	26,001	23,742
Net sales [Abstract]
Total consolidated net sales	23,861	26,001	23,742
Net sales
Total	23,861	26,001	23,742
Reportable Segment [Member] | Inter-segment sales [Member]
Segment Reporting Information [Line Items]
Net sales	74,854	59,795	33,430
Net sales [Abstract]
Total consolidated net sales	74,854	59,795	33,430
Net sales
Total	74,854	59,795	33,430
Adjustments [Member]
Segment Reporting Information [Line Items]
Interest expense	(2,387)	(2,515)	(2,588)
Income taxes	(4,089)	(8,734)	(2,895)
Depreciation and amortization	1,512	1,465	1,407
Other significant items [Abstract]
Interest income	(632)	(792)	(916)
Interest expense	(2,387)	(2,515)	(2,588)
Income taxes	(4,089)	(8,734)	(2,895)
Depreciation and amortization	1,512	1,465	1,407
Expenditures for segment assets	$ 754	$ 401	$ 508