Divestitures (Details) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($) stores	Mar. 31, 2016 USD ($) stores
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on disposal | $	$ 4.3	$ 6.2
Import Stores Divested [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of stores divested | stores	1	2