Investment Securities and Certificates of Deposit - Additional Information (Details) $ in Thousands, ¥ in Billions	3 Months Ended
	Mar. 31, 2020 USD ($)	Mar. 31, 2019 USD ($)	Feb. 29, 2020 USD ($)	Dec. 31, 2019 USD ($)	Mar. 31, 2019 JPY (¥)
Schedule Of Marketable Securities [Line Items]
Certificates of Deposit, at Carrying Value	$ 0			$ 214,796
Debt Securities [Member]
Schedule Of Marketable Securities [Line Items]
Investment Securities, Realized Gains (Losses)	(4)	$ (3)
Equity Securities [Member]
Schedule Of Marketable Securities [Line Items]
Investment Securities, Realized and Unrealized Gains (Losses)	(334)	152
Debt Securities Carried by Broker-Dealers [Member]
Schedule Of Marketable Securities [Line Items]
Investment Securities, Realized and Unrealized Gains (Losses)	(634)	49
Investment Funds [Member]
Schedule Of Marketable Securities [Line Items]
Investment Securities, Realized and Unrealized Gains (Losses)	$ (13,019)	6,587
Foreign Exchange Forward [Member]
Schedule Of Marketable Securities [Line Items]
Derivative Asset, Notional Amount		$ 35,598	$ 38,908		¥ 3.8