Supplemental Consolidating Financial Statements - Balance Sheet (Details) (USD $) In Thousands, unless otherwise specified	Oct. 25, 2014	Jul. 26, 2014	Oct. 26, 2013	Jul. 27, 2013
CURRENT ASSETS:
Cash and equivalents	$ 16,459	$ 20,672	$ 14,394	$ 18,607
Accounts receivable, net	296,832	272,741
Costs and estimated earnings in excess of billings	256,951	230,569
Inventories	47,003	49,095
Deferred tax assets, net	21,022	19,932
Other current assets	14,467	12,727
Total current assets	652,734	605,736
PROPERTY AND EQUIPMENT, NET	206,139	205,413
GOODWILL	269,465	269,088
INTANGIBLE ASSETS, NET	117,824	116,116
DEFERRED TAX ASSETS, NET NON-CURRENT	0	0
INVESTMENT IN SUBSIDIARIES	0	0
INTERCOMPANY RECEIVABLES	0	0
OTHER	15,995	16,001
TOTAL NON-CURRENT ASSETS	609,423	606,618
TOTAL ASSETS	1,262,157	1,212,354
CURRENT LIABILITIES:
Accounts payable	66,422	63,318
Current portion of debt	11,719	10,938
Billings in excess of costs and estimated earnings	14,027	13,882
Accrued insurance claims	33,525	32,260
Deferred tax liabilities	0	0
Other accrued liabilities	86,905	76,134
Total current liabilities	212,598	196,532
Long-term debt	455,640	446,863
ACCRUED INSURANCE CLAIMS	36,189	33,782
DEFERRED TAX LIABILITIES, NET NON-CURRENT	43,018	45,361
INTERCOMPANY PAYABLES	0	0
OTHER LIABILITIES	5,211	4,882
Total liabilities	752,656	727,420
Total stockholders' equity	509,501	484,934
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	1,262,157	1,212,354
Parent
CURRENT ASSETS:
Cash and equivalents	0	0	0	0
Accounts receivable, net	0	0
Costs and estimated earnings in excess of billings	0	0
Inventories	0	0
Deferred tax assets, net	4,001	3,822
Other current assets	7,434	4,956
Total current assets	11,435	8,778
PROPERTY AND EQUIPMENT, NET	17,743	18,108
GOODWILL	0	0
INTANGIBLE ASSETS, NET	0	0
DEFERRED TAX ASSETS, NET NON-CURRENT	403	182
INVESTMENT IN SUBSIDIARIES	830,423	809,617
INTERCOMPANY RECEIVABLES	0	0
OTHER	7,967	7,748
TOTAL NON-CURRENT ASSETS	856,536	835,655
TOTAL ASSETS	867,971	844,433
CURRENT LIABILITIES:
Accounts payable	1,159	3,083
Current portion of debt	11,719	10,938
Billings in excess of costs and estimated earnings	0	0
Accrued insurance claims	565	612
Deferred tax liabilities	0	0
Other accrued liabilities	20,437	12,668
Total current liabilities	33,880	27,301
Long-term debt	175,000	166,125
ACCRUED INSURANCE CLAIMS	707	778
DEFERRED TAX LIABILITIES, NET NON-CURRENT	0	0
INTERCOMPANY PAYABLES	145,716	162,127
OTHER LIABILITIES	3,167	3,168
Total liabilities	358,470	359,499
Total stockholders' equity	509,501	484,934
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	867,971	844,433
Issuer
CURRENT ASSETS:
Cash and equivalents	0	0	0	0
Accounts receivable, net	0	0
Costs and estimated earnings in excess of billings	0	0
Inventories	0	0
Deferred tax assets, net	0	0
Other current assets	2	16
Total current assets	2	16
PROPERTY AND EQUIPMENT, NET	0	0
GOODWILL	0	0
INTANGIBLE ASSETS, NET	0	0
DEFERRED TAX ASSETS, NET NON-CURRENT	0	0
INVESTMENT IN SUBSIDIARIES	1,565,469	1,540,338
INTERCOMPANY RECEIVABLES	0	0
OTHER	5,465	5,636
TOTAL NON-CURRENT ASSETS	1,570,934	1,545,974
TOTAL ASSETS	1,570,936	1,545,990
CURRENT LIABILITIES:
Accounts payable	0	0
Current portion of debt	0	0
Billings in excess of costs and estimated earnings	0	0
Accrued insurance claims	0	0
Deferred tax liabilities	80	80
Other accrued liabilities	5,492	566
Total current liabilities	5,572	646
Long-term debt	280,640	280,738
ACCRUED INSURANCE CLAIMS	0	0
DEFERRED TAX LIABILITIES, NET NON-CURRENT	432	432
INTERCOMPANY PAYABLES	453,869	454,557
OTHER LIABILITIES	0	0
Total liabilities	740,513	736,373
Total stockholders' equity	830,423	809,617
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	1,570,936	1,545,990
Subsidiary Guarantors
CURRENT ASSETS:
Cash and equivalents	15,801	19,739	13,631	18,166
Accounts receivable, net	293,310	269,760
Costs and estimated earnings in excess of billings	255,062	228,541
Inventories	47,003	49,095
Deferred tax assets, net	17,017	16,193
Other current assets	6,605	7,237
Total current assets	634,798	590,565
PROPERTY AND EQUIPMENT, NET	170,707	171,158
GOODWILL	269,465	269,088
INTANGIBLE ASSETS, NET	117,226	115,483
DEFERRED TAX ASSETS, NET NON-CURRENT	4,294	3,884
INVESTMENT IN SUBSIDIARIES	1,681	1,621
INTERCOMPANY RECEIVABLES	612,828	628,443
OTHER	2,420	2,466
TOTAL NON-CURRENT ASSETS	1,178,621	1,192,143
TOTAL ASSETS	1,813,419	1,782,708
CURRENT LIABILITIES:
Accounts payable	63,901	58,970
Current portion of debt	0	0
Billings in excess of costs and estimated earnings	14,027	13,882
Accrued insurance claims	32,900	31,599
Deferred tax liabilities	64	66
Other accrued liabilities	58,909	61,284
Total current liabilities	169,801	165,801
Long-term debt	0	0
ACCRUED INSURANCE CLAIMS	35,424	32,959
DEFERRED TAX LIABILITIES, NET NON-CURRENT	46,865	48,593
INTERCOMPANY PAYABLES	0	0
OTHER LIABILITIES	2,039	1,711
Total liabilities	254,129	249,064
Total stockholders' equity	1,559,290	1,533,644
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	1,813,419	1,782,708
Non-Guarantor Subsidiaries
CURRENT ASSETS:
Cash and equivalents	658	933	763	441
Accounts receivable, net	3,522	2,981
Costs and estimated earnings in excess of billings	1,889	2,028
Inventories	0	0
Deferred tax assets, net	177	87
Other current assets	426	518
Total current assets	6,672	6,547
PROPERTY AND EQUIPMENT, NET	17,689	16,147
GOODWILL	0	0
INTANGIBLE ASSETS, NET	598	633
DEFERRED TAX ASSETS, NET NON-CURRENT	35	15
INVESTMENT IN SUBSIDIARIES	0	0
INTERCOMPANY RECEIVABLES	0	0
OTHER	143	151
TOTAL NON-CURRENT ASSETS	18,465	16,946
TOTAL ASSETS	25,137	23,493
CURRENT LIABILITIES:
Accounts payable	1,362	1,265
Current portion of debt	0	0
Billings in excess of costs and estimated earnings	0	0
Accrued insurance claims	60	49
Deferred tax liabilities	29	24
Other accrued liabilities	2,067	1,616
Total current liabilities	3,518	2,954
Long-term debt	0	0
ACCRUED INSURANCE CLAIMS	58	45
DEFERRED TAX LIABILITIES, NET NON-CURRENT	453	417
INTERCOMPANY PAYABLES	13,243	11,759
OTHER LIABILITIES	5	3
Total liabilities	17,277	15,178
Total stockholders' equity	7,860	8,315
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	25,137	23,493
Eliminations and Reclassifications
CURRENT ASSETS:
Cash and equivalents	0	0	0	0
Accounts receivable, net	0	0
Costs and estimated earnings in excess of billings	0	0
Inventories	0	0
Deferred tax assets, net	(173)	(170)
Other current assets	0	0
Total current assets	(173)	(170)
PROPERTY AND EQUIPMENT, NET	0	0
GOODWILL	0	0
INTANGIBLE ASSETS, NET	0	0
DEFERRED TAX ASSETS, NET NON-CURRENT	(4,732)	(4,081)
INVESTMENT IN SUBSIDIARIES	(2,397,573)	(2,351,576)
INTERCOMPANY RECEIVABLES	(612,828)	(628,443)
OTHER	0	0
TOTAL NON-CURRENT ASSETS	(3,015,133)	(2,984,100)
TOTAL ASSETS	(3,015,306)	(2,984,270)
CURRENT LIABILITIES:
Accounts payable	0	0
Current portion of debt	0	0
Billings in excess of costs and estimated earnings	0	0
Accrued insurance claims	0	0
Deferred tax liabilities	(173)	(170)
Other accrued liabilities	0	0
Total current liabilities	(173)	(170)
Long-term debt	0	0
ACCRUED INSURANCE CLAIMS	0	0
DEFERRED TAX LIABILITIES, NET NON-CURRENT	(4,732)	(4,081)
INTERCOMPANY PAYABLES	(612,828)	(628,443)
OTHER LIABILITIES	0	0
Total liabilities	(617,733)	(632,694)
Total stockholders' equity	(2,397,573)	(2,351,576)
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ (3,015,306)	$ (2,984,270)