Stock Options (Aggregate Activity Under Stock Option Plans) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
Stock Options Aggregate Activity Under Stock Option Plans Details
Options outstanding at beginning of year	7,390,000
Options granted	1,910,000
Options exercised	1,298,000
Options forfeited/expired	373,000
Options outstanding at June 30, 2013	7,109,000
Weighted-average exercise price of options outstanding, beginning of year	$ 6.75
Weighted-average exercise price of options granted during period	$ 8.91
Weighted-average exercise price of options exercised during the period	$ 4.93
Weighted-average exercise price of options forfeited/expired during the period	$ 13.57
Weighted-average exercise price of options outstanding, at June 30, 2013	$ 7.27
Weighted-average remaining contractual term of options outstanding, at June 30, 2013	7 years 3 months 7 days
Aggregate intrinsic value of options outstanding, at June 30, 2013	$ 61,009
Options Vested and Expected to Vest, Number of Shares	7,109,000
Options Vested and Expected to Vest, Weighted-Average Exercise Price Per Share	$ 7.18
Options Vested and Expected to Vest, Weighted-Average Remaining Contractual Term	7 years 2 months 5 days
Options Vested and Expected to Vest, Aggregate Intrinsic Value	57,540
Options Exercisable, Number of Shares	3,614,000
Options Exercisable, Weighted-Average Exercise Price Per Share	$ 6.54
Options Exercisable, Weighted-Average Remaining Contractual Term	5 years 11 months 23 days
Options Exercisable, Aggregate Intrinsic Value	$ 32,144