Deposits Deposits (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Deposits [Abstract]
Interest bearing, demand and overnight	$ 660,692		$ 660,692		$ 611,432
Interest bearing, term	46,400		46,400		149,350
Interest bearing, other	4,539		4,539		4,521
Total interest-bearing	711,631		711,631		765,303
Non-interest bearing, other	1,493		1,493		576
Total non-interest bearing	1,493		1,493		576
Total deposits	$ 713,124		$ 713,124		$ 765,879
Weighted Average Rate, Interest-bearing Domestic Deposits, over Time	0.59%	0.15%	0.49%	0.14%