Common Stock and Other Equity Related Transactions - Additional Information (Detail) (USD $)	3 Months Ended
	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013
Class of Stock [Line Items]
Stockholders' Equity Note, Stock Split	On June 25, 2013, management announced a two-for-one split, to be effected by and in the form of a stock dividend, to take effect on July 15, 2013. On July 15, 2013, each common shareholder of record on July 5, 2013, received one additional share of common stock for each share held. On July 15, 2013, we effected a two-for-one stock split of our common stock, by and in the form of a stock dividend and was paid to stockholders of record on July 5, 2013.
Stockholders' Equity Note, Stock Split, Conversion Ratio	2
Common Stock
Class of Stock [Line Items]
Dividends Payable, Date to be Paid	Oct. 11, 2013	Jul. 12, 2013	Apr. 12, 2013
Common Stock, Dividends, Per Share, Cash Paid	$ 0.25	$ 0.25	$ 0.25
Dividends Payable, Date of Record	Sep. 27, 2013	Jun. 28, 2013	Mar. 28, 2013
Cumulative Series C Six Point Seven Five Percent Redeemable Perpetual Preferred Stock [Member]
Class of Stock [Line Items]
Dividends Payable, Date to be Paid	Sep. 30, 2013	Jul. 01, 2013	Apr. 01, 2013
Preferred Stock, Dividends, Per Share, Cash Paid	$ 0.421875	$ 0.421875	$ 0.421875
Dividends Payable, Date of Record	Sep. 20, 2013	Jun. 20, 2013	Mar. 21, 2013