Stockholders' Equity - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended			0 Months Ended	28 Months Ended	3 Months Ended	28 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Oct. 29, 2014 Subsequent Event [Member]	Sep. 30, 2014 Non-executive directors [Member] Restricted Stock [Member]	Sep. 30, 2014 2011 LTIP [Member] Restricted Stock Units [Member]	Sep. 30, 2014 2011 LTIP [Member] Restricted Stock Units [Member]	Jun. 30, 2014 2011 LTIP [Member] Restricted Stock Units [Member]	Sep. 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	$ 1,106,000	$ 946,000	$ 2,816,000	$ 2,200,000
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	21,675,735		21,675,735		21,652,341
Preferred stock outstanding	0		0		0
Restricted stock units awarded to CEO							47,855	0	557,484
Restricted stock unit forfeitures							3,189	0	209,382
Outstanding restricted stock units								559,689	559,689	559,689	642,582
Dividends declared						2,700,000
Stock Repurchase Program, Authorized Amount						15,000,000
Expected Amount For Dividends And/Or Common Stock Repurchases						26,000,000
Dividend rate						$ 0.125
Declaration date						Oct. 29, 2014
Record Date						Nov. 18, 2014
Payment Date						Dec. 10, 2014
Increase in additional paid-in capital			2,700,000
Additional paid-in capital	$ 130,040,000		$ 130,040,000		$ 127,264,000