Commitments and Contingencies (Details)	1 Months Ended				2 Months Ended	3 Months Ended
	Dec. 31, 2017 item	Sep. 30, 2015 pharmacy	Mar. 31, 2010 state	Feb. 28, 2006 lawsuit item director	Sep. 30, 2017 complaint	Mar. 31, 2018 item store
Loss contingencies
Number of store leases guaranteed | store						85
Number of material accruals for outstanding legal matters						0
Number of pharmacies indicated in subpoena | pharmacy		8
Omnicare, Inc.
Loss contingencies
New claims filed, number | lawsuit				2
Number of officers named in lawsuit				3
Number of directors named in lawsuit | director				2
Multi-state Investigation
Loss contingencies
Number of states participating in multi-state investigation | state			28
National Opioid Litigation
Loss contingencies
the number of relevant federal court cases that named the company	40
The number of relevant state court cases that named the company	20
Shareholder Matters
Loss contingencies
Number of complaints | complaint					4
Number of complaints filed in Rhode Island | complaint					3