Derivative Financial Instruments Fair Value Gains and Losses on Derivative Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Derivative [Line Items]
Net fair value gains (losses) on derivative financial instruments	$ 929	$ (2,016)	$ 769	$ 870
Interest rate lock with customers [Member]
Derivative [Line Items]
Net fair value gains (losses) on derivative financial instruments	178	1,041	1,922	876
Forward Commitments [Member]
Derivative [Line Items]
Net fair value gains (losses) on derivative financial instruments	970	(3,183)	(1,042)	(338)
Interest Rate Swap with Customer [Member]
Derivative [Line Items]
Net fair value gains (losses) on derivative financial instruments	(1,948)	18,266	48,052	17,831
Interest Rate Swap with Counterparty [Member]
Derivative [Line Items]
Net fair value gains (losses) on derivative financial instruments	1,948	(18,266)	(48,052)	(17,831)
Foreign Exchange Contracts With Customer [Member]
Derivative [Line Items]
Net fair value gains (losses) on derivative financial instruments	47	(197)	502	(378)
Foreign Exchange Contracts With Correspondent Banks [Member]
Derivative [Line Items]
Net fair value gains (losses) on derivative financial instruments	$ (266)	$ 323	$ (613)	$ 710