Operating Segments - Segment Detail (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended				6 Months Ended
	Dec. 26, 2014		Dec. 27, 2013		Dec. 26, 2014		Dec. 27, 2013
Segment Reporting Information [Line Items]
Sales Revenue, Services, Other	$ 143,228		$ 122,592		$ 266,253		$ 229,166
Net service revenue	99,838		91,131		192,457		172,383
Operating income (loss)	6,866		5,195		12,858		9,449
Corporate shared services(2)	(10,794)	[1]	(11,021)	[1]	(21,092)	[1]	(21,236)	[1]
Allocated Share-based Compensation Expense	(1,209)		(1,243)		(2,376)		(2,398)
Depreciation and amortization	(2,641)		(2,250)		(4,906)		(4,426)
Interest expense	(21)		(38)		(52)		(130)
Income from operations before taxes	6,845		5,157		12,806		9,319
Operating Segments
Segment Reporting Information [Line Items]
Sales Revenue, Services, Other	142,116		122,607		266,176		227,981
Net service revenue	99,138		90,902		193,140		170,655
Operating income (loss)	19,477		18,083		37,535		34,341
Depreciation and amortization	(2,033)		(1,626)		(3,697)		(3,168)
Reconciling Items
Segment Reporting Information [Line Items]
Sales Revenue, Services, Other	1,112		(15)		77		1,185
Net service revenue	700	[2]	229	[2]	(683)	[2]	1,728	[2]
Depreciation and amortization	(608)		(624)		(1,209)		(1,258)
Energy
Segment Reporting Information [Line Items]
Sales Revenue, Services, Other	42,446		40,106		80,481		73,570
Net service revenue	35,163		34,893		68,376		63,707
Operating income (loss)	7,907		7,301		13,548		11,405
Depreciation and amortization	(804)		(792)		(1,643)		(1,550)
Environmental
Segment Reporting Information [Line Items]
Sales Revenue, Services, Other	81,055		66,420		149,249		121,942
Net service revenue	52,555		44,560		100,211		82,921
Operating income (loss)	10,152		8,764		20,310		18,111
Depreciation and amortization	(1,111)		(726)		(1,823)		(1,406)
Infrastructure
Segment Reporting Information [Line Items]
Sales Revenue, Services, Other	18,615		16,081		36,446		32,469
Net service revenue	11,420		11,449		24,553		24,027
Operating income (loss)	1,418		2,018		3,677		4,825
Depreciation and amortization	$ (118)		$ (108)		$ (231)		$ (212)

[1] Corporate shared services consist of centrally managed functions in the following areas: accounting, treasury, information technology, legal, human resources, marketing, internal audit and executive management such as the CEO and various executives. These costs and other items of a general corporate nature are not allocated to the Company’s three operating segments.

[2] Amounts represent certain unallocated corporate amounts not considered in the CODM's evaluation of operating segment performance.