Derivative Financial Instruments Fair Value Gains and Losses on Derivative Financial Instruments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Derivative [Line Items]
Net fair value gains on derivative financial instruments	$ 623	$ 221
Interest rate lock with customers [Member]
Derivative [Line Items]
Net fair value gains on derivative financial instruments	845	1,232
Forward Commitments [Member]
Derivative [Line Items]
Net fair value gains on derivative financial instruments	(2,379)	(1,106)
Interest Rate Swap with Customer [Member]
Derivative [Line Items]
Net fair value gains on derivative financial instruments	(815)	29,431
Interest Rate Swap with Counterparty [Member]
Derivative [Line Items]
Net fair value gains on derivative financial instruments	3,001	(29,431)
Foreign Exchange Contracts With Customer [Member]
Derivative [Line Items]
Net fair value gains on derivative financial instruments	8	374
Foreign Exchange Contracts With Correspondent Banks [Member]
Derivative [Line Items]
Net fair value gains on derivative financial instruments	$ (37)	$ (279)