Summary of Significant Accounting Policies - Intangible Assets (Details)	12 Months Ended
	Mar. 31, 2021 USD ($) states reporting_unit	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	May 12, 2020 USD ($)	Apr. 01, 2020 USD ($)	Mar. 31, 2018 USD ($)
Finite-Lived Intangible Assets [Line Items]
Number of reporting units | reporting_unit	1
Share Repurchases [Abstract]
Amount authorized for repurchase				$ 30,000,000.0
Amount remaining for repurchase	$ 21,400,000
Stockholders' equity	$ 404,927,441	$ 411,963,067	$ 552,116,625			$ 541,107,852
Concentration of Risk [Abstract]
Number of states in which entity operates | states	16
Number of states with largest concentration of revenue | states	4
Advertising	$ 17,190,676	24,304,023	22,482,553
Allowance for credit losses	91,722,288	96,487,856	$ 81,519,624			$ 66,088,139
Retained Earnings (Accumulated Deficit)	(149,336,767)	(184,748,490)
Deferred income taxes, net	24,992,742	$ 23,257,985
Revolving Credit Facility
Share Repurchases [Abstract]
Amount outstanding	$ 405,000,000.0
Revenue Benchmark
Concentration of Risk [Abstract]
Concentration risk percentage	53.00%	56.00%	57.00%
Customer lists
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, useful life (in years)	9 years 6 months
Customer lists | Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, useful life (in years)	8 years
Customer lists | Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, useful life (in years)	23 years
Noncompete Agreements
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, useful life (in years)	5 years
Noncompete Agreements | Minimum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, useful life (in years)	3 years
Noncompete Agreements | Maximum
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets, useful life (in years)	5 years 3 months 18 days
Accounting Standards Update 2016-13
Concentration of Risk [Abstract]
Allowance for credit losses	$ 28,600,000				$ 28,600,000
Retained Earnings (Accumulated Deficit)					21,200,000
Deferred income taxes, net					$ 7,400,000