Insurance Operations - Statutory Capital and Surplus, and an Amount Representing Ten Percent of Total Liabilities for both UPCIC and APPCIC (Detail) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021
UPCIC
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	$ 400,866	$ 378,750
Ten percent of total liabilities	151,190	122,292
APPCIC
Statutory Accounting Practices [Line Items]
Statutory capital and surplus	22,786	16,104
Ten percent of total liabilities	$ 2,023	$ 649

The amount of statutory capital and surplus (stockholders' equity) as of the balance sheet date using prescribed or permitted statutory accounting practices (rather than GAAP, if different) of the state or country.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(23)(c))
-URI https://asc.fasb.org/extlink&oid=126734703&loc=d3e572229-122910

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI https://asc.fasb.org/extlink&oid=6486098&loc=d3e24708-158529

Name:	us-gaap_StatutoryAccountingPracticesStatutoryCapitalAndSurplusBalance
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant