Subsequent Events (Details) $ in Thousands	1 Months Ended	3 Months Ended						9 Months Ended
	Nov. 06, 2018 USD ($) store	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Sep. 30, 2018 USD ($) store	Sep. 30, 2017 USD ($)
Subsequent Event [Line Items]
Number of stores acquired | store								15
Purchase price to acquire real estate | $		$ 74,694	$ 237,284	$ 70,787	$ 31,966	$ 34,641	$ 25,556	$ 382,765	$ 92,163
Subsequent Event
Subsequent Event [Line Items]
Number of stores acquired | store	3
Purchase price to acquire real estate | $	$ 31,900