Stock Options (Aggregate Activity Under Stock Option Plans) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	9 Months Ended
	Sep. 30, 2013
Stock Options Aggregate Activity Under Stock Option Plans Details
Options outstanding at beginning of year	7,390,000
Options granted	2,107,000
Options exercised	1,995,000
Options forfeited/expired	361,000
Options outstanding at September 30, 2013	7,141,000
Weighted-average exercise price of options outstanding, beginning of year	$ 6.75
Weighted-average exercise price of options granted during period	$ 10.18
Weighted-average exercise price of options exercised during the period	$ 5.79
Weighted-average exercise price of options forfeited/expired during the period	$ 13.75
Weighted-average exercise price of options outstanding, at June 30, 2013	$ 7.67
Weighted-average remaining contractual term of options outstanding, at September 30, 2013	7 years 6 months 25 days
Aggregate intrinsic value of options outstanding, at September 30, 2013	$ 172,323
Options Vested and Expected to Vest, Number of Shares	6,676,000
Options Vested and Expected to Vest, Weighted-Average Exercise Price Per Share	$ 7.53
Options Vested and Expected to Vest, Weighted-Average Remaining Contractual Term	7 years 5 months 19 days
Options Vested and Expected to Vest, Aggregate Intrinsic Value	162,085
Options Exercisable, Number of Shares	3,614,000
Options Exercisable, Weighted-Average Exercise Price Per Share	$ 6.40
Options Exercisable, Weighted-Average Remaining Contractual Term	6 years 0 months 4 days
Options Exercisable, Aggregate Intrinsic Value	$ 79,723