Basis and Summary of Significant Accounting Policies - Lease Merchandise (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Significant Accounting Policies [Line Items]
Lease merchandise salvage value percentage	0.00%
Lease agreement, lease period used as asset useful life	12 months
Lease Merchandise, net of Accumulated Depreciation and Allowances	$ 1,196,812	$ 1,152,135
Components of the allowance of leases merchandise write-offs:
Beginning Balance	35,629	33,399
Merchandise Written off, net of Recoveries	(130,946)	(143,230)
Provision for Write-offs	146,091	145,460
Ending Balance	50,774	35,629
Merchandise on Lease
Significant Accounting Policies [Line Items]
Lease Merchandise, net of Accumulated Depreciation and Allowances	$ 933,569	908,268
Merchandise on Lease | Minimum
Significant Accounting Policies [Line Items]
Lease merchandise useful life	12 months
Merchandise on Lease | Maximum
Significant Accounting Policies [Line Items]
Lease merchandise useful life	24 months
Merchandise not on Lease
Significant Accounting Policies [Line Items]
Lease merchandise useful life	36 months
Lease Merchandise, net of Accumulated Depreciation and Allowances	$ 263,243	$ 243,867