Derivative Financial Instruments Derivative Financial Instruments (Narrative) (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Amount reclassified from accumulated other comprehensive income to interest expense	$ 2,400,000
Basis Amortization of Hedged item no longer in a Hedging Relationship	43,000	43,000
Loans Held-for-sale, Fair Value Disclosure	446,355,000	215,231,000	351,290,000
Derivative, Net Liability Position, Aggregate Fair Value	30,000,000
Interest Rate Cap [Member] | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of Interest Rate Derivatives Held	6
Notional amount	620,000,000
Interest Rate Contract | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	3,100,000,000
Forward Commitments to Sell Mortgage Loans
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	829,000,000
Interest Rate Lock Commitments
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	531,800,000
Foreign Exchange Contract
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	9,600,000
Call Options Written [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Number of Instruments Held	0	0	0
Minimum [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, maturity date	Apr. 30, 2015
Maximum [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, maturity date	Feb. 28, 2045
Cash Flow Hedging | Interest Rate Contract | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net	0	0
Fair Value Hedging | Interest Rate Swap [Member] | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of Interest Rate Derivatives Held	3
Notional amount	4,700,000
Fair Value Hedging | Interest Rate Contract | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Income Statement Gain/(Loss) due to Hedge Ineffectiveness	(4,000)	(2,000)
Cash flow hedge of variable rate deposits [Member] | Cash Flow Hedging | Interest Rate Cap [Member] | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of Interest Rate Derivatives Held	2
Interest Rate Cap Two Hundred Sixteen Million Five Hundred Thousand Notional August Two Thousand Sixteen Maturity | Cash Flow Hedging | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	216,500,000
Interest Rate Cap Forty Three Million Five Hundred Thousand Notional August Two Thousand Sixteen Maturity | Cash Flow Hedging | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	43,500,000
Cash Flow Hedge of Junior Subordinated Debentures | Cash Flow Hedging | Interest Rate Cap [Member] | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of Interest Rate Derivatives Held	2
Cash Flow Hedge of Junior Subordinated Debentures | Cash Flow Hedging | Interest Rate Swap [Member] | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of Interest Rate Derivatives Held	2
De-designated Hedge [Member] | Interest Rate Cap [Member] | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	$ 96,500,000