Summary of Significant Accounting Policies Narratives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Accounting Policies [Line Items]
Securities purchased under agreements to resell	$ 3,500,000	$ 6,499,000
Securities purchased under agreements to resell, average balance	5,500,000	4,000,000
Securties purchased under agreements to resell, maximum amount outstanding at any month-end	7,000,000	6,500,000
Real Estate Acquired Through Foreclosure	$ 1,300	$ 818
Quarterly percentage of net income contributed to restricted retained earnings per the Joint Capital Enhancement Agreement	20.00%
Percent of average balance of outstanding consolidated obligations prescribed per the Joint Capital Enhancement Agreement for each previous quarter	1.00%
Minimum [Member]
Accounting Policies [Line Items]
Premises, software, and equipment, useful life	3 years
Definition of related party, minimum percent	10.00%
Maximum [Member]
Accounting Policies [Line Items]
Premises, software, and equipment, useful life	10 years
Accounting Standards Update 2016-02 [Member]
Accounting Policies [Line Items]
Lease Right Of Use Asset	$ 10,300
Lease Liability	10,400
Other Expense [Member]
Accounting Policies [Line Items]
Operating Lease, Cost	$ 2,600