Derivatives - Summary of Gains Losses on Derivative Contracts Included in Condensed Consolidated Statements of Operations (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Rate lock commitments | Compensation and employee benefits
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in income for derivatives	$ 500	$ 200	$ (900)	$ (1,900)
Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in income for derivatives	(3,253)	(21,919)	(1,008)	(33,860)
Not Designated as Hedging Instrument | Nasdaq Forwards | Other income (loss), net
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in income for derivatives	(22,945)	(15,638)	(1,772)	(28,967)
Not Designated as Hedging Instrument | Rate lock commitments | Gains from mortgage banking activities/originations, net
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in income for derivatives	(10,208)	14,292	49,955	21,379
Not Designated as Hedging Instrument | Rate lock commitments | Compensation and employee benefits
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in income for derivatives	512	211	(899)	(1,856)
Not Designated as Hedging Instrument | Forward sale contracts | Gains from mortgage banking activities/originations, net
Derivative Instruments, Gain (Loss)
Gain (loss) recognized in income for derivatives	$ 29,388	$ (20,784)	$ (48,292)	$ (24,416)