Derivative Financial Instruments (Fair Value of Derivative Instruments) (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Derivatives Fair Value [Line Items]
Derivative Financial Liabilities, Gross Amounts Recognized	$ 58,146	$ 72,126
Derivative Financial Assets, Gross Amount Recognized	27,607	25,915
Interest Rate Contract [Member] | Other Assets [Member] | Designated As Hedging Instrument [Member]
Derivatives Fair Value [Line Items]
Derivative Financial Assets, Gross Amount Recognized	1,882	878
Interest Rate Contract [Member] | Other Assets [Member] | Not Designated As Hedging Instruments [Member]
Derivatives Fair Value [Line Items]
Derivative Financial Assets, Gross Amount Recognized	25,725	25,037
Interest Rate Contract [Member] | Other Liabilities [Member] | Designated As Hedging Instrument [Member]
Derivatives Fair Value [Line Items]
Derivative Financial Liabilities, Gross Amounts Recognized	37,837	51,172
Interest Rate Contract [Member] | Other Liabilities [Member] | Not Designated As Hedging Instruments [Member]
Derivatives Fair Value [Line Items]
Derivative Financial Liabilities, Gross Amounts Recognized	$ 20,309	$ 20,954