Variable Interest Entities (Summary of the Impact of Qualifying LIHTC Investments) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Low income housing tax credits
Variable Interest Entity [Line Items]
Amortization of qualifying LIHTC investments	$ 2,362	$ 2,330	$ 4,640	$ 4,628
Affordable Housing Tax Credits and Other Tax Benefits	(2,598)	(2,534)	(4,998)	(5,057)
Other tax benefits related to qualifying LIHTC investments
Variable Interest Entity [Line Items]
Affordable Housing Tax Credits and Other Tax Benefits	$ (910)	$ (1,069)	$ (1,829)	$ (2,179)