Redeemable Preferred Stock - Additional Information (Detail) (USD $)					3 Months Ended		6 Months Ended					1 Months Ended	6 Months Ended
	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 16, 2011	Jun. 30, 2013 Series A Redeemable Preferred Stock	Jun. 30, 2012 Series A Redeemable Preferred Stock	Jun. 30, 2013 Series A Redeemable Preferred Stock	Jun. 30, 2012 Series A Redeemable Preferred Stock	Dec. 31, 2012 Series A Redeemable Preferred Stock	Sep. 16, 2011 Series A Redeemable Preferred Stock	Sep. 15, 2011 Series A Redeemable Preferred Stock	Apr. 30, 2013 Series A Redeemable Preferred Stock Dividend Paid	Jun. 30, 2013 Series A Redeemable Preferred Stock Scenario 1	Jun. 30, 2013 Series A Redeemable Preferred Stock Scenario 2
Class of Stock [Line Items]
Preferred stock, shares authorized				100,000,000	100,000,000		100,000,000		100,000,000		2,000,000
Preferred stock, par/stated value	$ 0.01	$ 0.01	$ 0.01	$ 0.01	$ 1,000		$ 1,000		$ 1,000		$ 0.01
Liquidation preference											$ 1,000
Preferred stock, shares issued					75,767		75,767		75,767	125,000	125,000
Preferred Stock											$ 125,000,000
Percentage of unpaid dividends that may be paid with additional shares of Series A Preferred Stock							50.00%
Rate of Dividend accrual through March 15, 2012							10.00%
Rate of Dividend accrual through September 15, 2013							14.00%
Rate of Dividend accrual from September 16, 2013 to September 15, 2015							17.00%
Rate of Dividend accrual after September 16, 2015							20.00%
Redemption terms of series A preferred stock							Redemption price equal to the lesser of (1) an amount equal to 100% of such net cash proceeds and (2) the $125.0 million aggregate par value of the Series A Preferred Stock plus any accrued but unpaid dividends.
Redemption terms of series A preferred stock, percentage of issue price													100.00%
Redemption terms of series A preferred stock, aggregate par value														125,000,000
Dividends paid					2,700,000.0	3,300,000.0	5,400,000.0	6,500,000.0				2,700,000
Dividends accrued					2,700,000.0	4,400,000.0	5,400,000.0	7,700,000.0
Dividends accreted					$ 500,000.0	$ 2,400,000.0	$ 1,000,000.0	$ 4,800,000.0
Preferred stock outstanding					75,767		75,767