Notes Receivables - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest income recognized	$ 0	$ 595
Notes Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest income recognized	$ 0	$ 595
Notes Receivable on Nonaccrual Status	Effective January 1, 2020, notes receivable were placed on non-accrual status.
Advisor Engine [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impairment	$ 19,672
Advisor Engine [Member] | Unsecured Convertible Note Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impairment	2,126
Advisor Engine [Member] | Unsecured Non Convertible Note [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impairment	$ 17,546