Property, Plant and Equipment - Summary of Property, Plant and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 513,779	$ 450,310
Less: Accumulated Depreciation and Amortization	(284,287)	(242,623)
Property, Plant and Equipment, Net	229,492	207,687
Land
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	19,950	19,768
Buildings and Improvements
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	67,081	67,053
Leasehold Improvements and Signs
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	83,867	69,407
Fixtures and Equipment
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	210,747	180,553
Software - Internal Use
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	106,671	86,208
Assets Under Capital Leases | Related Party
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	872	4,032
Assets Under Capital Leases | Non-Related Party
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	9,487	12,426
Construction in Progress
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 15,104	$ 10,863