Fair Value Measurements - Change in Fair Value for Financial Instruments (Detail) (Loan Securities Carried at Fair Value [Member], Significant Unobservable Inputs (Level 3) [Member], USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Loan Securities Carried at Fair Value [Member] | Significant Unobservable Inputs (Level 3) [Member]
Fair Value Measurements, Recurring and Nonrecurring, Valuation Techniques [Line Items]
Fair value, Beginning Balance	$ 226	$ 11
Net unrealized gain	0	215
Fair value, Ending Balance	226	226
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	$ 0	$ 215