Goodwill and Other Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Aug. 27, 2016	Aug. 29, 2015	Aug. 27, 2016	Aug. 29, 2015	Feb. 27, 2016
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	$ 2,844,975		$ 2,844,975		$ 2,819,815
Accumulated Amortization	(1,957,127)		(1,957,127)		(1,848,936)
Net	887,848		887,848		970,879
Gross Carrying Amount of Indefinite Lived	33,500		33,500
Gross Carrying Amount, Total	2,878,475		2,878,475		2,853,315
Net, Total	921,348		921,348		1,004,379
Unfavorable lease intangibles	43,746		43,746		46,947
Amortization expense for intangible assets and liabilities	55,409	$ 48,609	110,912	$ 80,550
Anticipated annual amortization expense for intangible assets and liabilities
2017	216,319		216,319
2018	174,705		174,705
2019	137,295		137,295
2020	107,707		107,707
2021	74,994		74,994
Trademarks
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Indefinite Lived	33,500		33,500		33,500
Favorable leases and other
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	667,119		667,119		665,197
Accumulated Amortization	(522,417)		(522,417)		(507,776)
Net	144,702		$ 144,702		$ 157,421
Remaining Weighted Average Amortization Period			7 years		8 years
Prescription files
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	1,564,559		$ 1,564,559		$ 1,541,518
Accumulated Amortization	(1,338,015)		(1,338,015)		(1,285,633)
Net	226,544		$ 226,544		$ 255,885
Remaining Weighted Average Amortization Period			3 years		3 years
Customer relationships
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	465,000		$ 465,000		$ 465,000
Accumulated Amortization	(77,085)		(77,085)		(44,203)
Net	387,915		$ 387,915		$ 420,797
Remaining Weighted Average Amortization Period			16 years		17 years
CMS license
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	57,500		$ 57,500		$ 57,500
Accumulated Amortization	(2,722)		(2,722)		(1,572)
Net	54,778		$ 54,778		$ 55,928
Remaining Weighted Average Amortization Period			24 years		25 years
Claims adjudication and other developed software
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	59,197		$ 59,197		$ 59,000
Accumulated Amortization	(9,973)		(9,973)		(5,760)
Net	49,224		$ 49,224		$ 53,240
Remaining Weighted Average Amortization Period			6 years		7 years
Trademarks
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	20,100		$ 20,100		$ 20,100
Accumulated Amortization	(2,379)		(2,379)		(1,373)
Net	17,721		$ 17,721		$ 18,727
Remaining Weighted Average Amortization Period			9 years		10 years
Backlog
Finite Lived And Indefinite Lived Intangible Assets By Major Class
Gross Carrying Amount of Finite Lived	11,500		$ 11,500		$ 11,500
Accumulated Amortization	(4,536)		(4,536)		(2,619)
Net	$ 6,964		$ 6,964		$ 8,881
Remaining Weighted Average Amortization Period			2 years		3 years