Supplemental Consolidating Financial Statements - Income Statement (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jan. 25, 2014	Jan. 26, 2013	Jan. 25, 2014	Jan. 26, 2013
Revenues [Abstract]
Contract revenues	$ 390,518	$ 369,326	$ 903,238	$ 692,613
EXPENSES:
Cost of earned revenues, excluding depreciation and amortization	327,353	301,516	737,472	558,582
General and administrative	38,562	38,827	81,637	67,652
Depreciation and amortization	23,435	20,819	46,987	36,130
Intercompany charges (income), net	0	0	0	0
Total	389,350	361,162	866,096	662,364
Interest income (expense), net	(6,800)	(5,748)	(13,686)	(9,946)
Other income, net	595	428	2,607	2,042
INCOME BEFORE INCOME TAXES	(5,037)	2,844	26,063	22,345
PROVISION (BENEFIT) FOR INCOME TAXES	(1,970)	1,381	10,470	9,022
NET INCOME (LOSS) BEFORE EQUITY IN EARNINGS OF SUBSIDIARIES	(3,067)	1,463	15,593	13,323
EQUITY IN EARNINGS OF SUBSIDIARIES	0	0	0	0
NET INCOME	(3,067)	1,463	15,593	13,323
Foreign currency translation gain	(226)	11	(286)	13
COMPREHENSIVE INCOME (LOSS)	(3,293)	1,474	15,307	13,336
Parent
Revenues [Abstract]
Contract revenues	0	0	0	0
EXPENSES:
Cost of earned revenues, excluding depreciation and amortization	0	0	0	0
General and administrative	10,284	14,900	21,520	23,309
Depreciation and amortization	1,039	639	1,893	1,380
Intercompany charges (income), net	(13,130)	(17,380)	(27,106)	(27,306)
Total	(1,807)	(1,841)	(3,693)	(2,617)
Interest income (expense), net	(1,807)	(1,523)	(3,696)	(2,299)
Other income, net	0	(318)	3	(318)
INCOME BEFORE INCOME TAXES	0	0	0	0
PROVISION (BENEFIT) FOR INCOME TAXES	0	0	0	0
NET INCOME (LOSS) BEFORE EQUITY IN EARNINGS OF SUBSIDIARIES	0	0	0	0
EQUITY IN EARNINGS OF SUBSIDIARIES	(3,067)	1,463	15,593	13,323
NET INCOME	(3,067)	1,463	15,593	13,323
Foreign currency translation gain	(226)	11	(286)	13
COMPREHENSIVE INCOME (LOSS)	(3,293)	1,474	15,307	13,336
Issuer
Revenues [Abstract]
Contract revenues	0	0	0	0
EXPENSES:
Cost of earned revenues, excluding depreciation and amortization	0	0	0	0
General and administrative	215	148	441	295
Depreciation and amortization	0	0	0	0
Intercompany charges (income), net	0	0	0	0
Total	215	148	441	295
Interest income (expense), net	(4,994)	(4,224)	(9,988)	(7,644)
Other income, net	0	0	0	0
INCOME BEFORE INCOME TAXES	(5,209)	(4,372)	(10,429)	(7,939)
PROVISION (BENEFIT) FOR INCOME TAXES	(2,102)	(1,808)	(4,189)	(3,205)
NET INCOME (LOSS) BEFORE EQUITY IN EARNINGS OF SUBSIDIARIES	(3,107)	(2,564)	(6,240)	(4,734)
EQUITY IN EARNINGS OF SUBSIDIARIES	40	4,027	21,833	18,057
NET INCOME	(3,067)	1,463	15,593	13,323
Foreign currency translation gain	(226)	11	(286)	13
COMPREHENSIVE INCOME (LOSS)	(3,293)	1,474	15,307	13,336
Subsidiary Guarantors
Revenues [Abstract]
Contract revenues	388,402	366,797	897,832	685,822
EXPENSES:
Cost of earned revenues, excluding depreciation and amortization	325,678	299,106	733,373	552,650
General and administrative	25,322	21,279	54,266	38,895
Depreciation and amortization	21,230	18,969	42,851	32,255
Intercompany charges (income), net	13,271	17,718	27,380	27,990
Total	385,501	357,072	857,870	651,790
Interest income (expense), net	1	(1)	(2)	(3)
Other income, net	630	756	2,575	2,321
INCOME BEFORE INCOME TAXES	3,532	10,480	42,535	36,350
PROVISION (BENEFIT) FOR INCOME TAXES	1,485	4,540	17,085	14,676
NET INCOME (LOSS) BEFORE EQUITY IN EARNINGS OF SUBSIDIARIES	2,047	5,940	25,450	21,674
EQUITY IN EARNINGS OF SUBSIDIARIES	0	0	0	0
NET INCOME	2,047	5,940	25,450	21,674
Foreign currency translation gain	0	0	0	0
COMPREHENSIVE INCOME (LOSS)	2,047	5,940	25,450	21,674
Non-Guarantor Subsidiaries
Revenues [Abstract]
Contract revenues	2,116	2,529	5,406	6,791
EXPENSES:
Cost of earned revenues, excluding depreciation and amortization	1,675	2,410	4,099	5,932
General and administrative	2,741	2,500	5,410	5,153
Depreciation and amortization	1,166	1,211	2,243	2,495
Intercompany charges (income), net	(141)	(338)	(274)	(684)
Total	5,441	5,783	11,478	12,896
Interest income (expense), net	0	0	0	0
Other income, net	(35)	(10)	29	39
INCOME BEFORE INCOME TAXES	(3,360)	(3,264)	(6,043)	(6,066)
PROVISION (BENEFIT) FOR INCOME TAXES	(1,353)	(1,351)	(2,426)	(2,449)
NET INCOME (LOSS) BEFORE EQUITY IN EARNINGS OF SUBSIDIARIES	(2,007)	(1,913)	(3,617)	(3,617)
EQUITY IN EARNINGS OF SUBSIDIARIES	0	0	0	0
NET INCOME	(2,007)	(1,913)	(3,617)	(3,617)
Foreign currency translation gain	(226)	11	(286)	13
COMPREHENSIVE INCOME (LOSS)	(2,233)	(1,902)	(3,903)	(3,604)
Eliminations and Reclassifications
Revenues [Abstract]
Contract revenues	0	0	0	0
EXPENSES:
Cost of earned revenues, excluding depreciation and amortization	0	0	0	0
General and administrative	0	0	0	0
Depreciation and amortization	0	0	0	0
Intercompany charges (income), net	0	0	0	0
Total	0	0	0	0
Interest income (expense), net	0	0	0	0
Other income, net	0	0	0	0
INCOME BEFORE INCOME TAXES	0	0	0	0
PROVISION (BENEFIT) FOR INCOME TAXES	0	0	0	0
NET INCOME (LOSS) BEFORE EQUITY IN EARNINGS OF SUBSIDIARIES	0	0	0	0
EQUITY IN EARNINGS OF SUBSIDIARIES	3,027	(5,490)	(37,426)	(31,380)
NET INCOME	3,027	(5,490)	(37,426)	(31,380)
Foreign currency translation gain	452	(22)	572	(26)
COMPREHENSIVE INCOME (LOSS)	$ 3,479	$ (5,512)	$ (36,854)	$ (31,406)