Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2016	Mar. 25, 2016	Dec. 25, 2015	Sep. 25, 2015	Jun. 30, 2015	Mar. 27, 2015	Dec. 26, 2014	Sep. 26, 2014	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Gross revenue	$ 169,532	$ 158,130	$ 157,743	$ 135,459	$ 149,087	$ 130,777	$ 143,228	$ 123,025	$ 620,864	$ 546,117	$ 475,677
Net service revenue	132,331	121,253	111,382	100,163	114,567	100,994	99,838	92,619	465,129	408,018	354,956
Operating income (loss)	10,261	(23,302)	6,698	7,673	10,703	7,149	6,866	5,992	1,330	30,710	20,921
Income (loss) from operations before taxes and equity in (losses) earnings	9,630	(24,186)	6,374	7,645	10,694	7,076	6,845	5,961	(537)	30,576	20,752
Net income	5,942	(14,232)	3,935	4,488	6,758	5,160	3,997	3,481	133	19,396	12,010
Net income (loss) applicable to TRC Companies, Inc.	$ 5,909	$ (14,297)	$ 3,937	$ 4,492	$ 6,763	$ 5,165	$ 4,002	$ 3,485	$ 41	$ 19,415	$ 12,051
Basic earnings (loss) per common share (in dollars per share)	$ 0.19	$ (0.46)	$ 0.13	$ 0.15	$ 0.22	$ 0.17	$ 0.13	$ 0.12	$ 0.00	$ 0.64	$ 0.41
Diluted earnings (loss) per common share (in dollars per share)	$ 0.19	$ (0.46)	$ 0.13	$ 0.14	$ 0.22	$ 0.17	$ 0.13	$ 0.11	$ 0.00	$ 0.63	$ 0.40