Acquisitions - Narrative (Details) customer in Thousands, $ in Thousands		3 Months Ended			5 Months Ended
	Jul. 27, 2017 USD ($) customer state	Mar. 31, 2018 USD ($) store	Sep. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2017 USD ($) store
Business Acquisition [Line Items]
Payments to acquire businesses and asset acquisitions		$ 4,774		$ 580
SEI
Business Acquisition [Line Items]
Purchase price	$ 140,000
Number of customers entity serves | customer	90
Number of branded stores | state	104
Number of states in which entity operates | state	11
Revenue of acquiree since acquisition date		35,200			$ 58,300
Earnings or loss of acquiree since acquisition date		$ 4,200			$ 2,500
Weighted average useful life	5 years 1 month
Acquisition-related costs			$ 2,000
All Acquisitions Excluding SEI Acquisition
Business Acquisition [Line Items]
Number of franchised stores acquired | store		17			17
Payments to acquire businesses and asset acquisitions		$ 4,800		$ 600