Issuance Of Notes Payable And Warrants (Narrative) (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	0 Months Ended	9 Months Ended
	Aug. 21, 2008	Sep. 30, 2012
Issuance Of Notes Payable And Warrants [Line Items]
Principal amount of Senior Notes	$ 120,000
Principal amount of Senior Notes due, year	2020
Senior Notes coupon interest	5.20%
Senior Notes effective yield		7.94%
Warrant [Member] | Common Class A [Member]
Issuance Of Notes Payable And Warrants [Line Items]
Number of Class A Shares purchased, warrants	5,455
Class A Shares purchase price per share	$ 22.00
Senior Notes [Member]
Issuance Of Notes Payable And Warrants [Line Items]
Event of default under the indenture Accreted Amount due and payable, percentage		33.33%