Troubled Debts Restructured Defaulted (Detail) (Defaulted Loans, Commercial, USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013 Investment
Real estate
Financing Receivable, Modifications [Line Items]
No. of Loans	1
Post-Modification Outstanding Recorded Balance	$ 518
Other
Financing Receivable, Modifications [Line Items]
No. of Loans	1
Post-Modification Outstanding Recorded Balance	$ 109