Deposits - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Dec. 31, 2019
Banking and Thrift, Other Disclosures [Abstract]
Deposits	$ 23,592,119		$ 23,592,119		$ 24,283,983
Brokered deposits	12,800,000		12,800,000		13,800,000
Retail and other deposits	10,800,000		10,800,000		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	10,000	$ 8,000
Third party broker fees paid	1,000	$ 14,000	3,000	$ 15,000
Deposits exceeding FDIC insurance limits	663,000		663,000		963,000
Accrued interest on deposits	$ 56,000		$ 56,000		$ 68,000