Insurance Operations - Statutory Capital and Surplus, and an Amount Representing Ten Percent of Total Liabilities for both UPCIC and APPCIC (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Feb. 28, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Feb. 28, 2022
Statutory Accounting Practices [Line Items]
Capital Contributions - UPCIC		$ 92,000,000	$ 114,000	$ 0
Subordinated surplus debenture		20,000,000
Subsequent Event
Statutory Accounting Practices [Line Items]
Subordinated surplus debenture					$ 90,000,000
UPCIC (1) (2)
Statutory Accounting Practices [Line Items]
Statutory capital and surplus		378,750,000	360,707,000
Ten percent of total liabilities		122,292,000	98,682,000
Capital Contributions - UPCIC	$ 77,000,000	92,000,000	114,000,000	$ 0
UPCIC (1) (2) | Subsequent Event
Statutory Accounting Practices [Line Items]
Subordinated surplus debenture					$ 90,000,000
APPCIC
Statutory Accounting Practices [Line Items]
Statutory capital and surplus		16,104,000	12,918,000
Ten percent of total liabilities		$ 649,000	$ 1,793,000