Off-Balance Sheet Arrangements, Guarantees and Other Commitments - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2018
Commitments and Contingencies Disclosure [Line Items]
Deferred revenue	$ 598	$ 27,057		$ 736
Rent expense for premises and equipment leased under operating leases	$ 34,600	31,300	$ 24,800
Consolidated venture capital and private equity fund investments
Commitments and Contingencies Disclosure [Line Items]
Commitments expiration period	10 years
Unrestricted percentage of committed capital to call	100.00%
Consolidated venture capital and private equity fund investments | Lower Limit
Commitments and Contingencies Disclosure [Line Items]
Expected commitment period to invest in venture capital and private equity funds (in years)	5 years
Consolidated venture capital and private equity fund investments | Upper Limit
Commitments and Contingencies Disclosure [Line Items]
Expected commitment period to invest in venture capital and private equity funds (in years)	7 years
Standby Letter of Credit
Commitments and Contingencies Disclosure [Line Items]
Deferred revenue	$ 14,100	$ 12,400
Collateral in the form of cash	$ 1,200,000