Derivative Instruments (Detail) - Schedule of settlement of Fair Values Hedges (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Cumulative reduction to interest expense	$ 2,400		$ 2,500
Notes Payable and Debt [Member]
Cumulative reduction to interest expense	12,019	[1]	5,690	[1]
Remaining balance	9,605	[1]	15,933	[1]
Weighted average years remaining to maturity	2 years 5 months	[1]	3 years 1 month	[1]
Deposit Liability Contracts [Member]
Cumulative reduction to interest expense	11,070	[2]	3,780	[2]
Remaining balance	$ 138,415	[2]	$ 145,705	[2]
Weighted average years remaining to maturity	33 years 0 months	[2]	35 years 7 months	[2]

[1] Two fair value hedges of certain issues of the Company's notes payable and debt were settled on June 7, 2010 for a gain on settlement of $21.6 million..

[2] Three fair value hedges of certain of the Company's deposit liability contracts were settled on October 27, 2010 for a gain of $149.5 million.