Derivative Financial Instruments (Narrative) (Detail) (USD $)	3 Months Ended	6 Months Ended									3 Months Ended		6 Months Ended										6 Months Ended
	Jun. 30, 2013	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012	Jun. 30, 2013 Interest Rate Swaps And Caps [Member] Cash Flow Hedges [Member]	Jun. 30, 2013 Interest Rate Cap [Member] Cash Flow Hedges [Member] derivative_instruments	Dec. 31, 2012 Interest Rate Cap [Member] Other Income [Member]	Jun. 30, 2012 Interest Rate Cap [Member] Other Income [Member]	Jun. 30, 2013 Interest Rate Cap [Member] Not Designated as Hedging Instrument [Member]	Jun. 30, 2013 Interest Rate Contract [Member]	Jun. 30, 2013 Interest Rate Contract [Member] Other Income [Member]	Jun. 30, 2012 Interest Rate Contract [Member] Other Income [Member]	Jun. 30, 2013 Interest Rate Contract [Member] Other Income [Member]	Jun. 30, 2012 Interest Rate Contract [Member] Other Income [Member]	Jun. 30, 2013 Interest Rate Swap [Member] Cash Flow Hedges [Member] derivative_instruments	Jun. 30, 2013 Interest Rate Swap [Member] Other Income [Member]	Jun. 30, 2013 Forward Commitments To Sell Mortgage Loans [Member]	Jun. 30, 2013 Interest Rate Lock Commitments [Member]	Jun. 30, 2013 Foreign Exchange Contract [Member]	Jun. 30, 2013 Call Options Written [Member]	Dec. 31, 2012 Call Options Written [Member]	Jun. 30, 2012 Call Options Written [Member]	Jun. 30, 2013 Maximum [Member]	Jun. 30, 2013 Minimum [Member]	Jun. 30, 2013 Interest Rate Caps 2 [Member] Cash Flow Hedges [Member]	Jun. 30, 2013 Interest Rate Non-Hedging Cap 1 [Member] Not Designated as Hedging Instrument [Member]	Jun. 30, 2013 Interest Rate Non-Hedging Cap 2 [Member] Not Designated as Hedging Instrument [Member]	Jun. 30, 2013 Interest Rate Non-Hedging Cap 3 [Member] Not Designated as Hedging Instrument [Member]	Jun. 30, 2013 Interest Rate Non-Hedging Cap 4 [Member] Not Designated as Hedging Instrument [Member]	Jun. 30, 2013 Interest Rate Non-Hedging Cap 5 [Member] Not Designated as Hedging Instrument [Member]	Jun. 30, 2013 Interest Rate Non-Hedging Cap 6 [Member] Not Designated as Hedging Instrument [Member]	Jun. 30, 2013 Interest Rate Non-Hedging Cap 7 [Member] Not Designated as Hedging Instrument [Member]	Jun. 30, 2013 Interest Rate Caps 3 [Member] Cash Flow Hedges [Member]	Jun. 30, 2013 Interest Rate Caps 4 [Member] Cash Flow Hedges [Member]	Jun. 30, 2013 Total Interest Rate Cap [Member]	Jun. 30, 2013 Total Interest Rate Cap [Member] Cash Flow Hedges [Member]	Jun. 30, 2013 Interest Rate Caps 1 [Member] Cash Flow Hedges [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Net Liability Position, Aggregate Fair Value	$ 35,100,000	$ 35,100,000
Number of Interest Rate Derivatives Held						4									4
Amount reclassified from accumulated other comprehensive income to interest expense		2,900,000
Income Statement Gain/(Loss) due to Hedge Ineffectiveness											10,000	13,000	9,000	13,000
Fair value hedges recognized interest income	46,000	103,000
Notional Amount	315,000,000	315,000,000			315,000,000		96,500,000	96,500,000	880,000,000	2,500,000,000						4,200,000	1,000,000,000	496,200,000	4,800,000						40,000,000	77,000,000	215,000,000	96,530,000	216,500,000	100,000,000	100,000,000	75,000,000	50,000,000	40,000,000	1,030,030,000	150,000,000	20,000,000
Interest Rate Derivatives, at Fair Value, Net					(2,270,000)																				1,000	43,000	983,000	91,000	1,568,000	852,000	1,573,000	834,000	1,175,000	969,000	8,090,000	2,146,000	1,000
Mortgage loans held-for-sale	538,000,000	538,000,000
Derivative Asset, Fair Value, Net	38,118,000	38,118,000	47,546,000	45,430,000																0	0	0
Derivative, Maturity Date																							Jan. 31, 2033	Aug. 31, 2013
Collateral securities			$ 49,900,000