Junior Subordinated Debentures (Narrative) (Detail) (USD $) In Thousands, unless otherwise specified						6 Months Ended	9 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Jun. 30, 2014 Junior Subordinated Debt [Member] Rate	Jun. 30, 2014 Cash Flow Hedge of Junior Subordinated Debentures [Member] Cash Flow Hedging [Member] Designated as Hedging Instrument [Member] Interest Rate Swaps and Caps [Member]	Jun. 30, 2014 Cash Flow Hedge of Junior Subordinated Debentures [Member] Cash Flow Hedging [Member] Designated as Hedging Instrument [Member] Interest Rate Cap [Member]	Sep. 30, 2013 Cash Flow Hedge of Junior Subordinated Debentures [Member] Cash Flow Hedging [Member] Designated as Hedging Instrument [Member] Interest Rate Swap [Member]
Subordinated Borrowing [Line Items]
Percentage ownership interest in subsidiary trusts	100.00%
Common securities, approximate percentage of junior subordinated debentures	3.00%
Trust preferred securities, approximate percentage of junior subordinated debentures	97.00%
Junior subordinated debentures	$ 249,493	$ 249,493	$ 249,493
Debt, weighted average interest rate				2.42%
Notional amount					$ 225,000	$ 90,000
Number of Derivative Contracts						2	2
Derivative, maturity date							Sep. 30, 2013
Debt, hedge adjusted weighted average interest rate				3.14%
Consecutive quarters of deferred payment	20