Derivative Financial Instruments (Narrative) (Detail)	3 Months Ended		6 Months Ended
	Jun. 30, 2016 USD ($) contracts derivative_instruments	Jun. 30, 2015 USD ($) derivative_instruments	Jun. 30, 2016 USD ($) contracts derivative_instruments	Jun. 30, 2015 USD ($) derivative_instruments	Dec. 31, 2015 derivative_instruments
Derivative Instruments, Gain (Loss) [Line Items]
Amount reclassified from accumulated other comprehensive income to interest expense in the next twelve months			$ 1,700,000
Basis Amortization of Hedged item no longer in a Hedging Relationship	$ 43,000		86,000
Derivative, Net Liability Position, Aggregate Fair Value	$ 92,300,000		$ 92,300,000
Interest Rate Cap | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of Interest Rate Derivatives Held | contracts	3		3
Notional amount	$ 231,500,000		$ 231,500,000
Interest Rate Contract | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	3,800,000,000		3,800,000,000
Forward Commitments to Sell Mortgage Loans | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	1,200,000,000		1,200,000,000
Interest Rate Lock Commitments | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	655,300,000		655,300,000
Foreign Exchange Contract | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	$ 35,100,000		$ 35,100,000
Covered Call Options | Not Designated as Hedging Instrument
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, 2016
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 Swap | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Number of Interest Rate Derivatives Held | derivative_instruments	1		1
Notional amount	$ 250,000,000		$ 250,000,000
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	4		4
Notional amount	$ 24,700,000		$ 24,700,000
Fair Value Hedging | Interest Rate Contract | Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Income Statement Gain/(Loss) due to Hedge Ineffectiveness	$ 17,000	$ 2,000	$ (22,000)	$ (2,000)
Cash flow hedge of variable rate deposits | 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, $216.5 million, August 2016 | 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, $43.5 million, August 2016 | 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 | Interest Rate Cap | Not Designated as Hedging Instrument
Derivative Instruments, Gain (Loss) [Line Items]
Notional amount	$ 96,500,000		$ 96,500,000