Segments - Summary of Company's Assets by Reportable Segment (Detail) - USD ($) $ in Thousands	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	$ 1,124,721	$ 1,095,750	$ 1,092,465
Operating Segments | Franchise revenue
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	239,226		243,348
Operating Segments | Corporate-owned Stores
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	191,473		167,367
Operating Segments | Equipment revenue
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	185,594		206,632
Unallocated
Segment Reporting, Asset Reconciling Item [Line Items]
Total consolidated assets	$ 508,428		$ 475,118