Net Income per Share (Narrative) (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended										12 Months Ended
	Dec. 31, 2012 Stock Options [Member]	Dec. 31, 2011 Stock Options [Member]	Dec. 31, 2010 Stock Options [Member]	Dec. 31, 2012 Warrants [Member]	Dec. 31, 2011 Warrants [Member]	Dec. 31, 2012 Purchased Call Options [Member]	Dec. 31, 2011 Purchased Call Options [Member]	Dec. 31, 2012 Series 2012 Notes [Member]	Dec. 31, 2012 May 2015 Notes [Member]	May 16, 2011 May 2015 Notes [Member]	Dec. 31, 2012 February 2015 Notes [Member]	Dec. 31, 2012 2012 Notes [Member]	Dec. 31, 2012 2023 Notes [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate (in Percent)								2.875%	2.875%	3.75%	3.75%	2.00%	2.75%
Antidilutive securities excluded from computation of earnings per share (in Shares)	157,000	193,000	330,000	19,600,000	13,300,000	23,000,000	13,300,000
Maturity date of the debt instrument (Date)								Feb. 15, 2015	Feb. 15, 2015		May 01, 2015	Feb. 15, 2012	Aug. 16, 2023
Amount of convertible notes payable								$ 179,000