Fair Value Measurements - Change in Fair Value for Financial Instruments (Detail) (Significant Unobservable Inputs (Level 3) [Member], Loan Securities Carried at Fair Value [Member], USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Significant Unobservable Inputs (Level 3) [Member] | Loan Securities Carried at Fair Value [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value, Beginning Balance	$ 226	$ 11
Net unrealized gain
Fair value, Ending Balance	226	11
The amount of total gains or losses for the period included in earnings attributable to the change in unrealized gains or losses relating to assets still held at the reporting date