Business Combinations - Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed, Measurement Adjustments (Detail) - USD ($) $ in Thousands	13 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 14, 2022	Jul. 01, 2021
Business Acquisition [Line Items]
Goodwill	$ 487,909	$ 487,225
Adhesion Wealth
Business Acquisition [Line Items]
Total tangible assets acquired	6,122		$ 6,136
Total tangible assets, adjustment	(14)
Total liabilities assumed	(4,273)		(3,603)
Total liabilities assumed, adjustment	(670)
Identifiable intangible assets	8,300		8,300
Total intangible assets, adjustment	0
Goodwill	39,713		39,029
Goodwill, adjustment	684
Total net assets acquired	49,862		$ 49,862
Total net assets acquired, adjustment	$ 0
Voyant
Business Acquisition [Line Items]
Total liabilities assumed				$ (9,774)
Identifiable intangible assets				46,600
Goodwill				109,349
Total net assets acquired				$ 157,098