AdvisorEngine - Financial Interests carrying value of the Company's financial interests (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Total carrying amount - Assets	$ 36,284	$ 53,722
Total, Impairment	30,138
Advisor Engine [Member]
Unsecured convertible note, Gross Carrying Value	2,126
Unsecured non-convertible note, Gross Carrying Value	31,184
Preferred stock, Gross Carrying Value	25,000
Total gross carrying amount - Assets	58,310
Total carrying amount - Assets	28,172	53,722
Unsecured non-convertible note, Impairment	(5,138)
Preferred stock, Impairment	(25,000)
Total, Impairment	(30,138)
Unsecured convertible note, Net Carrying Value	2,126
Unsecured non-convertible note, Net Carrying Value	26,046	28,722
Preferred stock, Net Carrying Value	$ 0	25,000
Total, Net Carrying Value		$ 53,722