Derivative Instruments (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Derivative [Line Items]
Cash flow hedge gain (loss) to be reclassified within 12 months	$ 259
Deferred loss balance to loss on early extinguishment of debt	(197)
Remaining unamortized deferred gain (loss) balance of all previously terminated cash flow hedges	(324)		$ (597)
Remaining deferred gain (loss) balance on all previously terminated fair value hedges	2,200		4,000
Deferred gain balance on terminated fair value hedges expected to be reclassified from long-term debt	1,800
Deferred gain balance to loss on early extinguishment of debt	1,300
Derivative, fair value	1,400		1,400
Gain (loss) on sale of outstanding commitments	(933)	$ 5
Deferred gains (loss) on discontinuation of cash flow hedge reclassified to earnings	515	774
Reclassification of hedge-related basis adjustment as a reduction to loss on early extinguishment of debt	1,300
Fixed Rate Residential Mortgage [Member]
Derivative [Line Items]
Commitments to fund fixed-rate mortgage loans	99,200		88,800
Unrealized gain on fair value of fixed-rate mortgage loans to customers	782	$ 1,100
Sale of outstanding commitments	117,000		95,000
Interest Rate Swap [Member]
Derivative [Line Items]
Notional amount of interest rate swap contracts	1,270,000		$ 10,200
Federal Funds Sold [Member]
Derivative [Line Items]
Federal funds sold	74,000
Federal Funds Sold, Counterparty with CCC [Member]
Derivative [Line Items]
Federal funds sold	$ 21,700