Stockholders' Equity - Schedule of Dividends Paid (Detail) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Dividends Payable [Line Items]
Dividend Per Share	$ 0.25	$ 0.20	$ 0.70	$ 0.52
Installment One
Dividends Payable [Line Items]
Declaration Date			Jan. 31, 2013
Record Date			Mar. 06, 2013
Payment Date			Mar. 20, 2013
Dividend Per Share			$ 0.16
Installment Two
Dividends Payable [Line Items]
Declaration Date			May 02, 2013
Record Date			Jun. 05, 2013
Payment Date			Jun. 19, 2013
Dividend Per Share			$ 0.16
Installment Three
Dividends Payable [Line Items]
Declaration Date			Jul. 25, 2013
Record Date			Aug. 28, 2013
Payment Date			Sep. 11, 2013
Dividend Per Share			$ 0.20
Installment Four
Dividends Payable [Line Items]
Declaration Date			Oct. 22, 2013
Record Date			Nov. 25, 2013
Payment Date			Dec. 09, 2013
Dividend Per Share			$ 0.20
Installment Five
Dividends Payable [Line Items]
Declaration Date			Feb. 20, 2014
Record Date			Mar. 06, 2014
Payment Date			Mar. 20, 2014
Dividend Per Share			$ 0.20
Installment Six
Dividends Payable [Line Items]
Declaration Date			May 01, 2014
Record Date			Jun. 05, 2014
Payment Date			Jun. 19, 2014
Dividend Per Share			$ 0.25
Installment Seven
Dividends Payable [Line Items]
Declaration Date			Jul. 24, 2014
Record Date			Aug. 28, 2014
Payment Date			Sep. 11, 2014
Dividend Per Share			$ 0.25