Benefit Plans (Details 2) (USD $) In Thousands, except Per Share data	9 Months Ended
	Sep. 30, 2011
Stock option activity under the plans
Balance at December 31, 2010, Stock Options Outstanding	11,020
Balance at December 31, 2010, Weighted Average Exercise Price	$ 6.90
Options granted, Stock Options Outstanding	913
Options granted, Weighted Average Exercise Price	$ 9.20
Options exercised, Stock Options Outstanding	(1,748)
Options exercised, Weighted Average Exercise Price	$ 6.26
Options cancelled, Stock Options Outstanding	(721)
Options cancelled, Weighted Average Exercise Price	$ 7.83
Options expired, Stock Options Outstanding	404
Options expired, Weighted Average Exercise Price	$ 9.25
Balance at September 30, 2011, Stock Options Outstanding	9,060
Balance at September 30, 2011, Weighted Average Exercise Price	$ 7.08
Options vested and exercisable at September 30, 2011, Stock Options Outstanding	6,592
Options vested and expected-to-vest as of September 30, 2011, Stock Options Outstanding	8,955