Operating Segments - Segment Summary (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended												12 Months Ended
	Jun. 30, 2013	Mar. 29, 2013	Dec. 28, 2012	Sep. 28, 2012	Jun. 30, 2012		Mar. 30, 2012		Dec. 30, 2011		Sep. 30, 2011		Jun. 30, 2013 segments	Jun. 30, 2012	Jun. 30, 2011
Segment Reporting Information [Line Items]
Sales Revenue, Services, Other	$ 118,955	$ 109,806	$ 104,470	$ 108,286	$ 109,728		$ 101,118		$ 105,378		$ 103,735		$ 441,517	$ 419,959	$ 333,209
Number of operating segments (in segments)													3
Net service revenue	86,889	83,044	75,254	75,216	79,294		75,135		73,896		73,455		320,403	301,780	245,911
Segment profit	6,164	3,392	4,399	4,606	6,007	[1]	3,517	[1]	4,892	[1]	15,540	[1]	18,561	29,956	(7,572)
Depreciation and amortization													6,903	5,508	4,729
Total [Member]
Segment Reporting Information [Line Items]
Sales Revenue, Services, Other													438,949	417,020	330,834
Net service revenue													317,250	298,562	243,299
Segment profit													62,760	63,210	46,331
Depreciation and amortization													4,710	3,646	3,267
Energy
Segment Reporting Information [Line Items]
Sales Revenue, Services, Other													138,189	125,219	87,372
Net service revenue													109,815	96,018	71,625
Segment profit													23,261	23,517	15,744
Depreciation and amortization													1,868	1,171	993
Environmental
Segment Reporting Information [Line Items]
Sales Revenue, Services, Other													240,820	235,089	187,412
Net service revenue													163,217	159,016	129,396
Segment profit													30,836	31,955	24,764
Depreciation and amortization													2,397	1,996	1,708
Infrastructure
Segment Reporting Information [Line Items]
Sales Revenue, Services, Other													59,940	56,712	56,050
Net service revenue													44,218	43,528	42,278
Segment profit													8,663	7,738	5,823
Depreciation and amortization													$ 445	$ 479	$ 566

[1] A case titled The Arena Group v. TRC Environmental Corporation and TRC Companies, Inc., was filed in September 2007 and involved a former landlord seeking damages for alleged breach of a lease for certain office space in Houston, Texas that the subsidiary had vacated. The jury in that case returned an adverse verdict against the Company and its subsidiary TRC Environmental Corporation that was significantly in excess of our previously established litigation reserve. Therefore, in the fourth quarter of fiscal year 2011, the Company increased its litigation reserve by $17,278. Subsequently, the Company filed a post-trial motion to disregard the late fee portion of the verdict, which was granted on October 5, 2011, resulting in an $11,224 partial reversal of the previously recorded expense in first quarter of fiscal year 2012. In addition $163 of expense was recorded in the second quarter of fiscal year 2012 resulting in a net benefit of $11,061 for fiscal year 2012. A judgment was entered in the case on October 10, 2011, and on January 3, 2012 the Company paid $8,735 in full satisfaction of the judgment and interest. This adjustment was recorded on the Company's statement of operations under the caption Arena Towers Litigation (Reversal) Expense.