Derivative Financial Instruments (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Net Liability Position, Aggregate Fair Value	$ 54,600,000
Amount reclassified from accumulated other comprehensive income to interest expense	5,100,000
Fair value hedges recognized net reduction to interest income	118,000
Mortgage loans held-for-sale	412,200,000
Foreign currency derivative, notional amount	1,700,000
Cash collateral	6,600,000
Collateral securities	49,900,000
Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value hedges, interest rate with notional amount	2,200,000
Interest Rate Caps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value hedges, interest rate with notional amount	96,500,000
Fair value hedges non-designated notional amount	508,500,000
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value hedges non-designated notional amount	2,200,000,000
Forward Commitments to Sell Mortgage Loans [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	858,100,000	591,500,000
Interest Rate Lock Commitments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount	457,700,000	272,900,000
Call Options Written [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative assets	0	0
Cash Flow Hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate derivative, notional amount	225,000,000
Cash Flow Hedges [Member] | Interest Rate Swap [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Number of interest rate derivatives held	4
Cash Flow Hedges [Member] | Interest Rate Caps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Number of interest rate derivatives held	2
Cash Flow Hedges [Member] | Interest Rate Swaps and Caps [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest rate derivative, notional amount	225,000,000
Fair Value Hedges [Member] | Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Fair value of derivatives, hedge ineffectiveness	$ 55,000	$ 0
Minimum [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Lower Remaining Maturity Range	Mar. 31, 2013
Maximum [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Lower Remaining Maturity Range	Jan. 31, 2033