Derivative Financial Instruments Derivative Financial Instruments (Narrative) (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2015 USD ($) contracts derivative_instruments	Jun. 30, 2014 USD ($) derivative_instruments	Jun. 30, 2015 USD ($) contracts derivative_instruments	Jun. 30, 2014 USD ($) derivative_instruments	Dec. 31, 2014 USD ($) derivative_instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount reclassified from accumulated other comprehensive income to interest expense in the next twelve months			$ 2,800,000
Basis Amortization of Hedged item no longer in a Hedging Relationship	$ 43,000	$ 43,000	86,000	$ 86,000
Loans Held-for-sale, Fair Value Disclosure	497,283,000	$ 363,627,000	497,283,000	$ 363,627,000	$ 351,290,000
Derivative, Net Liability Position, Aggregate Fair Value	$ 35,400,000		$ 35,400,000
Interest Rate Cap | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of Interest Rate Derivatives Held | contracts	4		4
Notional amount	$ 446,500,000		$ 446,500,000
Interest Rate Contract | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	3,200,000,000		3,200,000,000
Forward Commitments to Sell Mortgage Loans
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	902,900,000		902,900,000
Interest Rate Lock Commitments
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	531,500,000		531,500,000
Foreign Exchange Contract
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	$ 14,000,000		$ 14,000,000
Covered Call Options
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Number of Instruments Held | derivative_instruments	0	0	0	0	0
Minimum | Interest Rate Contract | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, maturity date			Jul. 31, 2015
Maximum | Interest Rate Contract | Not Designated as Hedging Instrument
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 | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of Interest Rate Derivatives Held | derivative_instruments	3		3
Notional amount	$ 4,500,000		$ 4,500,000
Fair Value Hedging | Interest Rate Contract | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Income Statement Gain/(Loss) due to Hedge Ineffectiveness	$ 2,000	$ (1,000)	$ (2,000)	$ (3,000)
Cash flow hedge of variable rate deposits [Member] | Cash Flow Hedging | Interest Rate Cap | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of Interest Rate Derivatives Held | derivative_instruments	2		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		$ 216,500,000
Derivative, maturity date			Aug. 29, 2016
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		$ 43,500,000
Derivative, maturity date			Aug. 22, 2016
Cash Flow Hedge of Junior Subordinated Debentures | Cash Flow Hedging | Interest Rate Cap | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of Interest Rate Derivatives Held | derivative_instruments	2		2
Cash Flow Hedge of Junior Subordinated Debentures | Cash Flow Hedging | Interest Rate Swap | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of Interest Rate Derivatives Held | derivative_instruments	2		2
De-designated Hedge [Member] | Interest Rate Cap | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	$ 96,500,000		$ 96,500,000