Long-lived assets other than financial instruments, long-term customer relationships of a financial institution, mortgage and other servicing rights, deferred policy acquisition costs, and deferred tax assets.

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Segments - Additional Information (Detail)	3 Months Ended								12 Months Ended
Segments - Additional Information (Detail)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments \| segment									3
Number of operating segments \| segment									0
Total revenue	$ 174,359,000	$ 136,656,000	$ 140,550,000	$ 121,333,000	$ 134,028,000	$ 97,496,000	$ 107,316,000	$ 91,102,000	$ 572,898,000	$ 429,942,000	$ 378,241,000
Franchise revenue
Segment Reporting Information [Line Items]
Total revenue									224,140,000	150,155,000	116,488,000
Franchise revenue \| International
Segment Reporting Information [Line Items]
Total revenue									4,634,000	2,368,000	1,771,000
Franchise revenue \| Placement Services
Segment Reporting Information [Line Items]
Total revenue									11,502,000	11,371,000	10,513,000
Corporate-owned stores
Segment Reporting Information [Line Items]
Total revenue									138,599,000	112,114,000	104,721,000
Corporate-owned stores \| International
Segment Reporting Information [Line Items]
Total revenue									4,425,000	4,402,000	$ 4,180,000
Long-lived assets	$ 1,892,000				$ 2,558,000				1,892,000	$ 2,558,000
Intersegment Eliminations
Segment Reporting Information [Line Items]
Total revenue									$ 0