Term Debt (Narrative) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Debt Disclosure [Abstract]
Term debt	$ 888,769	$ 1,006,395
Maximum outstanding FHLB advances at any month end	1,000,000	1,100,000
Average outstanding FHLB advances	$ 919,100	$ 842,100
Average interest rate on borrowings	1.90%	1.60%