Derivative Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Derivative Financial Instruments Not Designated as Hedging Instruments
Asset Derivatives	$ 25,579	$ 42,610
Liability Derivatives	24,451	33,626
Interest Rate Lock Commitments
Derivative Financial Instruments Not Designated as Hedging Instruments
Asset Derivatives	2,214	10,188
Liability Derivatives	0	0
Forward Commitments
Derivative Financial Instruments Not Designated as Hedging Instruments
Asset Derivatives	12	189
Liability Derivatives	1,072	329
Interest Rate Swap Agreements
Derivative Financial Instruments Not Designated as Hedging Instruments
Asset Derivatives	23,176	32,193
Liability Derivatives	23,348	32,441
Foreign Exchange Contracts
Derivative Financial Instruments Not Designated as Hedging Instruments
Asset Derivatives	177	40
Liability Derivatives	$ 31	$ 856