Investments - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Investments, Debt and Equity Securities [Abstract]
Unrealized gain, net of other expenses	$ 114,000	$ 241,000	$ 152,000	$ 42,000