Derivative Financial Instruments (Narrative) (Detail) (USD $)	3 Months Ended	9 Months Ended											9 Months Ended						3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Interest Rate Cap [Member] De-designated Hedge [Member]	Sep. 30, 2013 Interest Rate Cap [Member] Not Designated as Hedging Instrument [Member] contracts	Sep. 30, 2013 Interest Rate Contract [Member] Not Designated as Hedging Instrument [Member]	Sep. 30, 2013 Forward Commitments to Sell Mortgage Loans [Member]	Sep. 30, 2013 Interest Rate Lock Commitments [Member]	Sep. 30, 2013 Foreign Exchange Contract [Member]	Sep. 30, 2013 Call Options Written [Member] derivative_instruments	Dec. 31, 2012 Call Options Written [Member] derivative_instruments	Sep. 30, 2012 Call Options Written [Member] derivative_instruments	Sep. 30, 2013 Minimum [Member]	Sep. 30, 2013 Maximum [Member]	Sep. 30, 2013 Cash Flow Hedging [Member] Interest Rate Swap [Member] Designated as Hedging Instrument [Member] derivative_instruments	Sep. 30, 2013 Cash Flow Hedging [Member] Interest Rate Cap [Member] Designated as Hedging Instrument [Member] derivative_instruments	Sep. 30, 2013 Cash Flow Hedging [Member] Interest Rate Swaps and Caps [Member] Designated as Hedging Instrument [Member]	Sep. 30, 2013 Fair Value Hedging [Member] Interest Rate Swap [Member] Designated as Hedging Instrument [Member] derivative_instruments	Sep. 30, 2013 Fair Value Hedging [Member] Interest Rate Contract [Member] Designated as Hedging Instrument [Member]	Sep. 30, 2012 Fair Value Hedging [Member] Interest Rate Contract [Member] Designated as Hedging Instrument [Member]	Sep. 30, 2013 Fair Value Hedging [Member] Interest Rate Contract [Member] Designated as Hedging Instrument [Member]	Sep. 30, 2012 Fair Value Hedging [Member] Interest Rate Contract [Member] Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Number of Interest Rate Derivatives Held										0	0	0			2	4		3
Derivative, Number of Instruments Held					7
Notional Amount	$ 225,000,000	$ 225,000,000		$ 96,500,000	$ 880,000,000	$ 2,700,000,000	$ 653,100,000	$ 323,300,000	$ 2,600,000								$ 225,000,000	$ 6,300,000
Amount reclassified from accumulated other comprehensive income to interest expense		2,000,000
Income Statement Gain/(Loss) due to Hedge Ineffectiveness																			0	37,000	9,000	50,000
Fair value hedges recognized interest income	10,000	17,000
Basis Amortization of Hedged item no longer in a Hedging Relationship	43,000	149,000
Derivative, Maturity Date													Oct. 31, 2013	Jan. 31, 2033
Mortgage loans held-for-sale	334,300,000	334,300,000
Derivative, Net Liability Position, Aggregate Fair Value	31,700,000	31,700,000
Security Owned and Pledged as Collateral, Fair Value			$ 49,900,000