Issuance of Notes Payable and Warrants - Additional Information (Detail) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified			9 Months Ended	1 Months Ended	9 Months Ended	1 Months Ended
	Sep. 30, 2013 Class A [Member]	Dec. 31, 2012 Class A [Member]	Sep. 30, 2013 Class A [Member] Maximum [Member]	Aug. 21, 2008 Senior Notes [Member]	Sep. 30, 2013 Senior Notes [Member]	Aug. 21, 2008 Warrant [Member] Class A [Member]
Issuance Of Notes Payable And Warrants [Line Items]
Principal amount of senior notes				$ 120,000,000
Principal amount of senior notes due, year				2020
Senior Notes coupon interest (as a percent)				5.20%
Warrants to purchase Class A shares (in shares)						5,455
Class A Common stock par value (in dollars per share)	$ 0.01	$ 0.01				$ 0.01
Class A Shares purchase price per share (in dollars per share)						$ 22.00
Senior notes effective yield (as a percent)					7.94%
Event of default under the indenture accreted amount due and payable (as a percent)					33.33%
Maximum percent of aggregate principal amount of senior notes owned by holder or group of affiliates for transfer (as a percent)					15.00%
Maximum percent of voting securities and total shares of class A common stock owned by holder or group of affiliates for warrant transfer (as a percent)	2.00%
Percent of outstanding shares of common stock owned by holder or group of affiliates for warrant transfer (as a percent)			25.00%