Summary of Significant Accounting Policies - Property, Plant and Equipment (Details) $ in Thousands		2 Months Ended	10 Months Ended	12 Months Ended
	Jun. 24, 2015	Mar. 03, 2018 USD ($)	Dec. 31, 2017 $ / Point	Mar. 03, 2018 USD ($) Point	Mar. 04, 2017 USD ($)	Feb. 27, 2016 USD ($)
Intangible Assets
Estimated Useful Life				10 years
Estimated useful life of purchased prescription files acquired in other than business combinations				5 years
Deferred Financing Costs
Amortization expenses of deferred financing costs				$ 8,403	$ 4,696	$ 4,691
Advertising
Advertising expenses, net of vendor advertising allowances				$ 161,826	$ 181,438	$ 191,534
Income Taxes
Federal statutory rate (as a percent)		21.00%	35.00%	32.60%	35.00%	35.00%
American Express Travel Related Services Company, Inc.
Revenue Recognition
Deferred revenue		$ 23,907		$ 23,907	$ 35,642
Value of each point earned by customer based on qualifying purchases at participating retailers under the program Plenti | $ / Point			0.01
Trade names
Intangible Assets
Finite-lived intangible assets amortization period				10 years
Customer relationships
Intangible Assets
Finite-lived intangible assets amortization period				15 years	16 years
Customer relationships | EnvisionRx
Intangible Assets
Estimated Useful Life	17 years
CMS license
Intangible Assets
Finite-lived intangible assets amortization period				23 years	24 years
CMS license | EnvisionRx
Intangible Assets
Estimated Useful Life	25 years
Minimum
Insurance
Workers compensation occurrences		1,000		$ 1,000
General liability occurrences		3,000		$ 3,000
Minimum | American Express Travel Related Services Company, Inc.
Revenue Recognition
Period for expiration of earned points by customer based on qualifying purchases at participating retailers if not redeemed under the program Plenti (in years)			2 years
Minimum | Customer relationships | EnvisionRx
Intangible Assets
Finite-lived intangible assets amortization period				10 years
Maximum | Customer relationships | EnvisionRx
Intangible Assets
Finite-lived intangible assets amortization period				20 years
Buildings | Minimum
Property, Plant and Equipment
Useful life				30 years
Buildings | Maximum
Property, Plant and Equipment
Useful life				45 years
Equipment | Minimum
Property, Plant and Equipment
Useful life				3 years
Equipment | Maximum
Property, Plant and Equipment
Useful life				15 years
Internal-use software
Property, Plant and Equipment
Capitalized costs				$ 13,940	$ 6,189	$ 7,680
Retail Pharmacy
Revenue Recognition
Number of points awarded for each dollar spent towards front end merchandise | Point				1
Number of points awarded for each qualifying prescription | Point				25
Accumulated number of points in a calendar year to achieve the "Gold" tier | Point				1,000
Percentage discount on qualifying purchases of front end merchandise on achieving "Gold" tier				20.00%
Deferred revenue		63,851		$ 63,851	60,255
Deferred revenue included in other current liabilities		50,036		50,036	46,864
Deferred revenue included in noncurrent liabilities		$ 13,815		$ 13,815	$ 13,391
Pharmacy Services
Vendor Rebates and Allowances and Purchase Discounts
Period for rebates are dispensed to manufacturers				30 days