Loans - Pre-Modification and Post-Modification Outstanding Recorded Investments (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011 Lease
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of finance leases		9
Pre-Modification Outstanding Recorded Investment	$ 99,494	$ 46,749
Post-Modification Outstanding Recorded Investment	90,348	46,346
Finance leases [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Pre-Modification Outstanding Recorded Investment		372
Post-Modification Outstanding Recorded Investment		$ 294