Fair Value Measurements - Difference Between Fair Values and the Aggregate Contractual Amounts (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2013
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fair Value at June 30, 2013	$ 226
Amount Due Upon Maturity	1,130
Difference	904
Loan Securities Carried at Fair Value [Member]
Fair Value Of Assets And Liabilities Measured On Non Recurring Basis [Line Items]
Fair Value at June 30, 2013	226
Amount Due Upon Maturity	1,130
Difference	$ 904