Debt - Schedule of Maturity Amounts Outstanding Under Credit Agreement and Senior Unsecured Notes (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2020	Dec. 31, 2021
Line of Credit Facility [Line Items]
Borrowings under credit agreement, outstanding amount	$ 70,000		$ 60,000
Borrowings under note purchase and guarantee agreement, outstanding amount	623,492		523,850
Total	695,000		585,000
Unamortized debt issuance costs, net	3,545		3,880
Total debt, net	$ 691,455		581,120
Revolving Facility [Member]
Line of Credit Facility [Line Items]
Maturity Date	Oct. 27, 2025
Interest Rate	5.60%
Borrowings under credit agreement, outstanding amount	$ 70,000		60,000
Total	$ 70,000
Series B Notes Maturing in June 2023 [Member]
Line of Credit Facility [Line Items]
Maturity Date	Jun. 02, 2023
Interest Rate	5.35%
Borrowings under note purchase and guarantee agreement, outstanding amount	$ 75,000		75,000
Series C Notes Maturing in February 2025 [Member]
Line of Credit Facility [Line Items]
Maturity Date	Feb. 25, 2025	Feb. 25, 2025
Interest Rate	4.75%
Borrowings under note purchase and guarantee agreement, outstanding amount	$ 50,000		50,000
Series D-E Notes Maturing in June 2028 [Member]
Line of Credit Facility [Line Items]
Maturity Date	Jun. 21, 2028
Interest Rate	5.47%
Borrowings under note purchase and guarantee agreement, outstanding amount	$ 100,000		100,000
Series F-H Notes Maturing in September 2029 [Member]
Line of Credit Facility [Line Items]
Maturity Date	Sep. 12, 2029
Interest Rate	3.52%
Borrowings under note purchase and guarantee agreement, outstanding amount	$ 125,000		125,000
Series I-K Notes Maturing in November 2030 [Member]
Line of Credit Facility [Line Items]
Maturity Date	Nov. 25, 2030
Interest Rate	3.43%
Borrowings under note purchase and guarantee agreement, outstanding amount	$ 175,000		$ 175,000
Series L-N Notes Maturing in February 2032 [Member]
Line of Credit Facility [Line Items]
Maturity Date	Feb. 22, 2032
Interest Rate	3.45%
Borrowings under note purchase and guarantee agreement, outstanding amount	$ 100,000
Series D Notes Maturing in June 2028 [Member]
Line of Credit Facility [Line Items]
Maturity Date		Jun. 21, 2028
Series E Notes Maturing in June 2028 [Member]
Line of Credit Facility [Line Items]
Maturity Date		Jun. 21, 2028
Series F Notes Maturing in September 2029 [Member]
Line of Credit Facility [Line Items]
Maturity Date		Sep. 12, 2029
Series G Notes Maturing in September 2029 [Member]
Line of Credit Facility [Line Items]
Maturity Date		Sep. 12, 2029
Series H Notes Maturing in September 2029 [Member]
Line of Credit Facility [Line Items]
Maturity Date		Sep. 12, 2029
Series I Notes Maturing in November 2030 [Member]
Line of Credit Facility [Line Items]
Maturity Date		Nov. 25, 2030
Series J Notes Maturing in November 2030 [Member]
Line of Credit Facility [Line Items]
Maturity Date		Nov. 25, 2030
Series K Notes Maturing in November 2030 [Member]
Line of Credit Facility [Line Items]
Maturity Date		Nov. 25, 2030