Equity (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012 Y
Stock options
Stock option awards, Shares
Outstanding at the beginning of the period (in shares)	2,106
Granted (in shares)	10
Exercised (in shares)	(38)
Forfeited (including cancelled options) (in shares)	(40)
Outstanding at the end of the period (in shares)	2,038
Options exercisable at the end of the period (in shares)	967
Weighted Average Exercise price
Outstanding at the beginning of the period (in dollars per share)	$ 25.58
Granted (in dollars per share)	$ 23.58
Exercised (in dollars per share)	$ 14.11
Forfeited (including cancelled options) (in dollars per share)	$ 29.42
Outstanding at the end of the period (in dollars per share)	$ 25.71
Options exercisable at the end of the period (in dollars per share)	$ 18.47
Aggregate Intrinsic Value
Outstanding at the end of the period (in dollars)	$ 16,662
Options exercisable at the end of the period (in dollars)	$ 10,841
Weighted Average Remaining Contractual Life
Outstanding at the end of the period (in years)	5.8
Options exercisable at the end of the period (in years)	4.3
Restricted Stock and Restricted Stock Units
Restricted stock awards including restricted stock units, Shares
Nonvested at the beginning of the period (in shares)	618
Granted (in shares)	9
Vested (in shares)	(10)
Forfeited (including cancelled awards) (in shares)	(25)
Nonvested at the end of the period (in shares)	592
Weighted-Average Grant-Date Fair Value
Nonvested at the beginning of the period (in dollars per share)	$ 33.61
Granted (in dollars per share)	$ 25.87
Vested (in dollars per share)	$ 30.88
Forfeited (including cancelled awards) (in dollars per share)	$ 31.54
Nonvested at the end of the period (in dollars per share)	$ 33.63