Deposits - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Banking and Thrift, Other Disclosures [Abstract]
Deposits	$ 23,109,923		$ 23,109,923		$ 24,283,983
Brokered deposits	12,100,000		12,100,000		13,800,000
Retail and other deposits	11,000,000		11,000,000		10,500,000
Stable interest-bearing deposits, total	7,100,000		7,100,000		6,800,000
Brokered deposit placement fee	5,000	$ 4,000	15,000	$ 12,000
Third party broker fees paid	2,000	$ 5,000	5,000	$ 20,000
Deposits exceeding FDIC insurance limits	681,000		681,000		963,000
Accrued interest on deposits	$ 64,000		$ 64,000		$ 68,000