Subsequent Events (Detail) (USD $) In Millions, except Share data, unless otherwise specified	3 Months Ended		1 Months Ended		0 Months Ended	1 Months Ended		1 Months Ended
	Mar. 31, 2012	Mar. 31, 2012 Roust Trading [Member] Forecasted Strategic Transaction [Member]	Apr. 23, 2012 Subsequent Event [Member] Senior Notes Due 2013 [Member]	Apr. 23, 2012 Subsequent Event [Member] Senior Notes Due 2013 [Member] Forecasted Strategic Transaction [Member]	May 04, 2012 Subsequent Event [Member] Roust Trading [Member] Forecasted Strategic Transaction [Member]	Apr. 23, 2012 Subsequent Event [Member] Roust Trading [Member] Senior Notes Due 2013 [Member] Forecasted Strategic Transaction [Member]	May 04, 2012 Subsequent Event [Member] Roust Trading [Member] Senior Notes Due 2013 [Member] Forecasted Strategic Transaction [Member]	Apr. 23, 2012 Subsequent Event [Member] Roust Trading [Member] Senior Rollover Notes Due 2016 [Member] Forecasted Strategic Transaction [Member]	Apr. 23, 2012 Subsequent Event [Member] Roust Trading [Member] Senior Backstop Notes Due 2016 [Member] Forecasted Strategic Transaction [Member]	Apr. 23, 2012 Subsequent Event [Member] Roust Trading [Member] Senior Rollover And Backstop Notes Due 2016 [Member] Forecasted Strategic Transaction [Member]
Subsequent Event [Line Items]
Company common stock to be purchased, shares				13,333,333	5,714,286
Company common stock to be purchased, value					$ 30
Company common stock to be purchased, price per share			$ 5.25		$ 5.25
Debt instrument issuance amount							$ 70.0	$ 102.6	$ 107.5
Debt instrument maturity date	Mar. 15, 2013	Jul. 31, 2016				Mar. 18, 2013		Jul. 31, 2016	Jul. 31, 2016
Interest rate percentage on issued debt		6.00%				3.00%				6.00%