Derivatives - Summary of Gains Losses on Derivative Contracts Included in Condensed Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Rate lock commitments | Compensation and employee benefits
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in income for derivatives	$ 1,400	$ 2,100
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in income for derivatives	2,245	(11,941)
Not Designated as Hedging Instrument | Nasdaq Forwards | Other income (loss), net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in income for derivatives	21,173	(13,329)
Not Designated as Hedging Instrument | Rate lock commitments | Gains from mortgage banking activities/originations, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in income for derivatives	60,163	7,087
Not Designated as Hedging Instrument | Rate lock commitments | Compensation and employee benefits
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in income for derivatives	(1,411)	(2,067)
Not Designated as Hedging Instrument | Forward sale contracts | Gains from mortgage banking activities/originations, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) recognized in income for derivatives	$ (77,680)	$ (3,632)