Supplemental Consolidating Financial Statements - Balance Sheet (Details) (USD $) In Thousands, unless otherwise specified	Apr. 26, 2014	Jul. 27, 2013	Apr. 27, 2013	Dec. 03, 2012	Jul. 28, 2012
CURRENT ASSETS:
Cash and equivalents	$ 18,722	$ 18,607	$ 18,247		$ 52,581
Accounts receivable, net	233,276	252,202
Costs and estimated earnings in excess of billings	198,581	204,349
Inventories	42,512	35,999
Deferred tax assets, net	17,156	16,853
Income taxes receivable	12,287	2,516
Other current assets	18,656	10,608
Total current assets	541,190	541,134
PROPERTY AND EQUIPMENT, NET	205,703	202,703
GOODWILL	267,810	267,810		87,900
INTANGIBLE ASSETS, NET	111,819	125,275
DEFERRED TAX ASSETS, NET NON-CURRENT	0	0
INVESTMENT IN SUBSIDIARIES	0	0
INTERCOMPANY RECEIVABLES	0	0
OTHER	16,254	17,286
TOTAL NON-CURRENT ASSETS	601,586	613,074
TOTAL ASSETS	1,142,776	1,154,208
CURRENT LIABILITIES:
Accounts payable	62,985	77,954
Current portion of debt	10,156	7,813
Billings in excess of costs and estimated earnings	13,401	13,788
Accrued insurance claims	32,567	29,069
Deferred Tax Liabilities, Net, Current	0	0
Other accrued liabilities	69,758	71,191
Total current liabilities	188,867	199,815
Long-term debt	403,082	444,169
ACCRUED INSURANCE CLAIMS	32,027	27,250
DEFERRED TAX LIABILITIES, NET NON-CURRENT	47,915	48,612
INTERCOMPANY PAYABLES	0	0
OTHER LIABILITIES	5,960	6,001
Total liabilities	677,851	725,847
Total stockholders' equity	464,925	428,361
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	1,142,776	1,154,208
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	2,993	2,285
Income taxes receivable	12,287	2,516
Other current assets	5,995	2,563
Total current assets	21,275	7,364
PROPERTY AND EQUIPMENT, NET	17,696	13,779
GOODWILL	0	0
INTANGIBLE ASSETS, NET	0	0
DEFERRED TAX ASSETS, NET NON-CURRENT	240	691
INVESTMENT IN SUBSIDIARIES	793,127	769,639
INTERCOMPANY RECEIVABLES	0	0
OTHER	8,165	8,739
TOTAL NON-CURRENT ASSETS	819,228	792,848
TOTAL ASSETS	840,503	800,212
CURRENT LIABILITIES:
Accounts payable	2,953	2,042
Current portion of debt	10,156	7,813
Billings in excess of costs and estimated earnings	0	0
Accrued insurance claims	634	619
Deferred Tax Liabilities, Net, Current	0	0
Other accrued liabilities	7,390	9,151
Total current liabilities	21,133	19,625
Long-term debt	122,250	163,062
ACCRUED INSURANCE CLAIMS	750	726
DEFERRED TAX LIABILITIES, NET NON-CURRENT	0	0
INTERCOMPANY PAYABLES	228,239	185,296
OTHER LIABILITIES	3,206	3,142
Total liabilities	375,578	371,851
Total stockholders' equity	464,925	428,361
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	840,503	800,212
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
Income taxes receivable	0	0
Other current assets	33	10
Total current assets	33	10
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	1,518,317	1,472,559
INTERCOMPANY RECEIVABLES	0	0
OTHER	5,800	6,331
TOTAL NON-CURRENT ASSETS	1,524,117	1,478,890
TOTAL ASSETS	1,524,150	1,478,900
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, Net, Current	155	155
Other accrued liabilities	5,525	1,321
Total current liabilities	5,680	1,476
Long-term debt	280,832	281,107
ACCRUED INSURANCE CLAIMS	0	0
DEFERRED TAX LIABILITIES, NET NON-CURRENT	427	427
INTERCOMPANY PAYABLES	444,084	426,251
OTHER LIABILITIES	0	0
Total liabilities	731,023	709,261
Total stockholders' equity	793,127	769,639
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	1,524,150	1,478,900
Subsidiary Guarantors
CURRENT ASSETS:
Cash and equivalents	18,009	18,166	17,631		51,563
Accounts receivable, net	231,574	249,533
Costs and estimated earnings in excess of billings	197,150	202,651
Inventories	42,512	35,999
Deferred tax assets, net	14,386	15,873
Income taxes receivable	0	0
Other current assets	12,137	7,583
Total current assets	515,768	529,805
PROPERTY AND EQUIPMENT, NET	173,061	173,254
GOODWILL	267,810	267,810
INTANGIBLE ASSETS, NET	111,151	125,275
DEFERRED TAX ASSETS, NET NON-CURRENT	4,042	4,104
INVESTMENT IN SUBSIDIARIES	954	0
INTERCOMPANY RECEIVABLES	680,660	618,524
OTHER	2,114	2,133
TOTAL NON-CURRENT ASSETS	1,239,792	1,191,100
TOTAL ASSETS	1,755,560	1,720,905
CURRENT LIABILITIES:
Accounts payable	59,103	75,012
Current portion of debt	0	0
Billings in excess of costs and estimated earnings	13,401	13,788
Accrued insurance claims	31,865	28,342
Deferred Tax Liabilities, Net, Current	131	140
Other accrued liabilities	55,034	59,374
Total current liabilities	159,534	176,656
Long-term debt	0	0
ACCRUED INSURANCE CLAIMS	31,210	26,426
DEFERRED TAX LIABILITIES, NET NON-CURRENT	51,342	52,436
INTERCOMPANY PAYABLES	0	0
OTHER LIABILITIES	2,753	2,855
Total liabilities	244,839	258,373
Total stockholders' equity	1,510,721	1,462,532
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	1,755,560	1,720,905
Non-Guarantor Subsidiaries
CURRENT ASSETS:
Cash and equivalents	713	441	616		1,018
Accounts receivable, net	1,702	2,669
Costs and estimated earnings in excess of billings	1,431	1,698
Inventories	0	0
Deferred tax assets, net	91	121
Income taxes receivable	0	0
Other current assets	491	452
Total current assets	4,428	5,381
PROPERTY AND EQUIPMENT, NET	14,946	15,670
GOODWILL	0	0
INTANGIBLE ASSETS, NET	668	0
DEFERRED TAX ASSETS, NET NON-CURRENT	211	66
INVESTMENT IN SUBSIDIARIES	0	0
INTERCOMPANY RECEIVABLES	0	0
OTHER	175	83
TOTAL NON-CURRENT ASSETS	16,000	15,819
TOTAL ASSETS	20,428	21,200
CURRENT LIABILITIES:
Accounts payable	929	900
Current portion of debt	0	0
Billings in excess of costs and estimated earnings	0	0
Accrued insurance claims	68	108
Deferred Tax Liabilities, Net, Current	28	1,131
Other accrued liabilities	1,809	1,345
Total current liabilities	2,834	3,484
Long-term debt	0	0
ACCRUED INSURANCE CLAIMS	67	98
DEFERRED TAX LIABILITIES, NET NON-CURRENT	639	610
INTERCOMPANY PAYABLES	8,337	6,977
OTHER LIABILITIES	1	4
Total liabilities	11,878	11,173
Total stockholders' equity	8,550	10,027
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	20,428	21,200
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	(314)	(1,426)
Income taxes receivable	0	0
Other current assets	0	0
Total current assets	(314)	(1,426)
PROPERTY AND EQUIPMENT, NET	0	0
GOODWILL	0	0
INTANGIBLE ASSETS, NET	0	0
DEFERRED TAX ASSETS, NET NON-CURRENT	(4,493)	(4,861)
INVESTMENT IN SUBSIDIARIES	(2,312,398)	(2,242,198)
INTERCOMPANY RECEIVABLES	(680,660)	(618,524)
OTHER	0	0
TOTAL NON-CURRENT ASSETS	(2,997,551)	(2,865,583)
TOTAL ASSETS	(2,997,865)	(2,867,009)
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, Net, Current	(314)	(1,426)
Other accrued liabilities	0	0
Total current liabilities	(314)	(1,426)
Long-term debt	0	0
ACCRUED INSURANCE CLAIMS	0	0
DEFERRED TAX LIABILITIES, NET NON-CURRENT	(4,493)	(4,861)
INTERCOMPANY PAYABLES	(680,660)	(618,524)
OTHER LIABILITIES	0	0
Total liabilities	(685,467)	(624,811)
Total stockholders' equity	(2,312,398)	(2,242,198)
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ (2,997,865)	$ (2,867,009)