Convertible Notes Tender Offer (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended	1 Months Ended	3 Months Ended
	Dec. 31, 2011	Apr. 30, 2011 4.50% Convertible Notes due 2012	Jun. 30, 2011 4.50% Convertible Notes due 2012
Cash paid to repurchase principal:
Allocated to liability component			$ 231,331
Allocated to equity component			1,632
Cash paid to repurchase principal		232,963	232,963
Carrying value of liability component tendered:
Principal amount of Convertible notes tendered		225,085	225,085
Pro rata share of original issue discount			(13,429)
Debt Instrument, Convertible, Carrying Amount of The Liability Component			211,656
Loss on extinguishment of debt:
Excess of liability component over carrying value			19,675
Write-off of pro rata share of debt issuance costs			2,147
Non-cash portion of loss on extinguishment of debt	22,456		21,822
Transaction costs and fees paid			2,416
Pre-tax loss on extinguishment	$ 25,421		$ 24,238