Stock Options (Aggregate Activity Under Stock Option Plans) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Stock Options Aggregate Activity Under Stock Option Plans Details
Options outstanding at beginning of year	7,390,000
Options granted	1,717,000
Options exercised	57,000
Options forfeited/expired	141,000
Options outstanding at end of year	8,909,000
Weighted-average exercise price of options outstanding, beginning of year	$ 6.75
Weighted-average exercise price of options granted during period	$ 8.29
Weighted-average exercise price of options exercised during the period	$ 3.34
Weighted-average exercise price of options forfeited/expired during the period	$ 6.00
Weighted-average exercise price of options outstanding, end of year	$ 7.08
Weighted-average remaining contractual term of options outstanding, end of year	7.23
Aggregate intrinsic value of options outstanding, end of year	$ 32,294
Options Vested and Expected to Vest, Number of Shares	8,322,000
Options Vested and Expected to Vest, Weighted-Average Exercise Price Per Share	$ 7.02
Options Vested and Expected to Vest, Weighted-Average Remaining Contractual Term	7.08
Options Vested and Expected to Vest, Aggregate Intrinsic Value	31,007
Options Exercisable, Number of Shares	4,731,000
Options Exercisable, Weighted-Average Exercise Price Per Share	$ 6.67
Options Exercisable, Weighted-Average Remaining Contractual Term	5.60
Options Exercisable, Aggregate Intrinsic Value	$ 21,205