Common Stock and Other Equity Related Transactions - Additional Information (Detail) (USD $)	3 Months Ended
	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014
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, 2014	Jun. 30, 2014	Mar. 31, 2014
Preferred Stock, Dividends, Per Share, Cash Paid	$ 0.421875	$ 0.421875	$ 0.421875
Dividends Payable, Date of Record	Sep. 19, 2014	Jun. 20, 2014	Mar. 21, 2014
Common Stock
Class of Stock [Line Items]
Dividends Payable, Date to be Paid	Oct. 10, 2014	Jul. 11, 2014	Apr. 11, 2014
Common Stock, Dividends, Per Share, Cash Paid	$ 0.325	$ 0.325	$ 0.325
Dividends Payable, Date of Record	Sep. 26, 2014	Jun. 27, 2014	Mar. 28, 2014