Leases (Narrative) (Details) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019 USD ($) stores	Jun. 30, 2019 USD ($) stores
Leases
Future minimum sublease income under non-cancelable subleases	$ 17.0	$ 17.0
Related parties [Member]
Related Parties
Number of stores \| stores	74	74
Lease payments under related party operating leases	$ 1.2	$ 2.4

Amount of transactions with related party during the financial reporting period.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration