Derivative Financial Instruments (Narrative) (Detail) (USD $)	12 Months Ended			1 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Interest Rate Swaps With Upstream Financial Institution Counterparties [Member]	Oct. 31, 2007 Variable-Rate Loans Outstanding [Member]	Dec. 31, 2007 Variable-Rate Loans Outstanding [Member]	Dec. 31, 2013 Junior Subordinated Deferred Interest Debentures [Member]	Oct. 31, 2008 Junior Subordinated Deferred Interest Debentures [Member]	Dec. 31, 2013 Effective Cash Flow Hedges [Member]	Dec. 31, 2012 Effective Cash Flow Hedges [Member]
Derivative [Line Items]
Total notional amount					$ 1,200,000,000		$ 120,000,000
Principal amount outstanding of variable-rate loans				1,200,000,000
Period for which cash flow hedges were used to hedge monthly interest receipts				84 months
Deferred accumulated gain	30,600,000	68,000,000
Deferred accumulated after-tax gain	19,900,000	44,200,000
Deferred gain in earning	30,600,000
Deferred after-tax gain in earning	19,900,000
Period for which cash flow hedges were used to hedge quarterly interest payments						5 years
Swap fixed interest rate to be paid						5.47%
Variable interest rate of three-month LIBOR plus a margin						1.55%
Weighted-average strike rate for outstanding interest rate caps	2.89%
Accumulated other comprehensive income net of tax								19,900,000	41,600,000
Approximate credit exposure related to swaps with bank customers	34,700,000		2,500,000
Aggregate fair value of securities posted as collateral for derivative contracts	$ 29,500,000