CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	6 Months Ended	12 Months Ended
	Jan. 27, 2018 USD ($)	Jan. 26, 2019 USD ($)	Jul. 29, 2017 USD ($)	Jul. 30, 2016 USD ($)
OPERATING ACTIVITIES:
Net income	$ 68,835	$ 62,907	$ 157,217	$ 128,740
Adjustments to reconcile net income to net cash provided by operating activities, net of acquisitions:
Depreciation and amortization	85,053	179,603	147,906	124,940
Deferred income tax provision (benefit)	(19,665)	8,523	18,233	26,782
Stock-based compensation	13,277	20,187	20,805	16,850
Bad debt expense, net	201	17,071	199	1,252
Gain on sale of fixed assets	(7,217)	(19,390)	(14,866)	(9,806)
Gain (Loss) on Extinguishment of Debt	0	0	0	16,260
Amortization Of Premium On Long-Term Debt	0	0	0	(94)
Amortization of debt discount	9,170	19,103	17,610	14,709
Amortization of debt issuance costs and other	1,736	3,686	3,323	2,875
Excess tax benefit from share-based awards	0	0	(8,385)	(13,003)
Change in operating assets and liabilities:
Accounts receivable, net	50,955	(30,750)	(33,068)	2,729
Contract assets, net	16,982	(149,828)	(27,773)	(70,957)
Other current assets and inventories	(67)	(15,842)	(13,232)	(13,800)
Other assets	1,630	(25,110)	2,064	(2,936)
Income taxes receivable/payable	(6,716)	10,357	(13,189)	20,148
Accounts payable	(21,503)	20,064	977	15,132
Accrued liabilities, insurance claims, and other liabilities	(32,138)	23,866	(1,378)	15,910
Net cash provided by operating activities	160,533	124,447	256,443	275,731
INVESTING ACTIVITIES:
Capital expenditures	0	(20,917)	(26,070)	(157,183)
Cash paid for acquisitions, net of cash acquired	(87,839)	(164,963)	(201,197)	(186,011)
Proceeds from sale of assets	11,808	22,949	16,029	10,540
Other investing activities	0	0	1,825	0
Other investing activities	0	1,576	666	0
Net cash used in investing activities	(76,031)	(161,355)	(208,747)	(332,654)
FINANCING ACTIVITIES:
Proceeds from borrowings on senior credit agreement, including term loans	0	423,188	707,000	1,310,000
Principal payments on senior credit agreement, including term loans	(9,625)	(331,250)	(685,563)	(1,209,000)
Repurchase of common stock	(16,875)	0	(62,909)	(169,997)
Proceeds from issuance of 0.75% convertible senior notes due 2021	0	0	0	485,000
Proceeds from sale of warrants	0	0	0	74,690
Purchase of convertible note hedge	0	0	0	(115,818)
Principal payments for satisfaction and discharge of 7.125% senior subordinated notes	0	0	0	(277,500)
Payment for Debt Extinguishment or Debt Prepayment Cost	0	0	0	(14,243)
Debt issuance costs	0	(7,275)	(70)	(16,376)
Exercise of stock options	745	871	1,449	2,745
Restricted stock tax withholdings	(12,581)	(4,657)	(10,767)	(12,604)
Excess tax benefit from share-based awards	0	0	8,385	13,003
Net cash provided by (used in) financing activities	(38,336)	80,877	(42,475)	69,900
Net increase in cash and equivalents and restricted cash	46,166	43,969	5,221	12,977
CASH AND EQUIVALENTS AND RESTRICTED CASH AT BEGINNING OF PERIOD		84,029
CASH AND EQUIVALENTS AND RESTRICTED CASH AT END OF PERIOD	84,029	128,342
SUPPLEMENTAL DISCLOSURE OF OTHER CASH FLOW ACTIVITIES AND NON-CASH INVESTING AND FINANCING ACTIVITIES:
Cash paid for interest	7,748	22,312	16,505	15,917
Cash paid for taxes, net	4,749	6,396	88,060	31,159
Purchases of capital assets included in accounts payable or other accrued liabilities at period end	1,634	6,795	21,978	7,196
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents	$ 90,182	$ 134,151	$ 44,016	$ 38,795