Fair Value - Changes in Fair Value for Items Measured at Fair Value Pursuant to Election of the Fair Value (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Schedule of Trading Securities and Other Trading Assets [Line Items]
Interest income (expense)	$ 145,671	$ 155,230	$ 289,442	$ 302,278
Interest (Expense)	(16,303)	(33,833)	(40,531)	(65,703)
Residential loans held for sale
Schedule of Trading Securities and Other Trading Assets [Line Items]
Other Gains and (Losses)	3,597	1,085	5,018	1,175
Interest income (expense)	0	5	2	10
Interest (Expense)	(2)	0	(2)	0
Total Changes in Fair Values Included in Current Period Earnings	$ 3,595	$ 1,090	$ 5,018	$ 1,185