Stockholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended		6 Months Ended			0 Months Ended	25 Months Ended	3 Months Ended	25 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Dec. 31, 2013	Jul. 30, 2014 Subsequent Event [Member]	Jun. 30, 2014 Non-executive directors [Member] Restricted Stock [Member]	Jun. 30, 2014 2011 LTIP [Member] Restricted Stock Units [Member]	Jun. 30, 2014 2011 LTIP [Member] Restricted Stock Units [Member]	Mar. 31, 2014 2011 LTIP [Member] Restricted Stock Units [Member]	Jun. 30, 2013 2011 LTIP [Member] Restricted Stock Units [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Amortization of stock based compensation	$ 624,000	$ 628,000	$ 1,710,000	$ 1,254,000
Common stock authorized	75,000,000		75,000,000
Common stock par value	$ 0.0001		$ 0.0001
Preferred stock authorized	25,000,000		25,000,000
Preferred stock par value	$ 0.0001		$ 0.0001
Common stock outstanding	21,663,909		21,663,909		21,652,341
Preferred stock outstanding	0		0		0
Restricted stock units awarded to CEO							41,849	0	557,484
Restricted stock unit forfeitures							3,189	57,338	209,382
Outstanding restricted stock units								559,689	559,689	617,027	508,118
Dividends declared						2,700,000
Dividend rate						$ 0.125
Declaration date						Jul. 30, 2014
Record Date						Aug. 19, 2014
Payment Date						Sep. 10, 2014
Increase in additional paid-in capital			1,700,000
Additional paid-in capital	$ 128,988,000		$ 128,988,000		$ 127,264,000