Investment Securities Available for Sale (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2015 USD ($) securities
Investments [Abstract]
Pledged to secure deposits | $	$ 2,120,000		$ 2,430,000
Securities in a loss position for less than twelve months | securities			64
Securities in a loss position for more than twelve months | securities			29
Other-than-temporary impairment charges | $	$ 88	$ 264