Equity (Details 2) (USD $) In Thousands, except Per Share data, unless otherwise specified	6 Months Ended
	Jun. 30, 2012
Stock options
Stock option awards, Shares
Outstanding at the beginning of the period (in shares)	2,106
Granted (in shares)	687
Exercised (in shares)	(143)
Forfeited (including cancelled options) (in shares)	(52)
Outstanding at the end of the period (in shares)	2,598
Options exercisable at the end of the period (in shares)	1,414
Weighted Average Exercise price
Outstanding at the beginning of the period (in dollars per share)	$ 25.58
Granted (in dollars per share)	$ 32.56
Exercised (in dollars per share)	$ 15.05
Forfeited (including cancelled options) (in dollars per share)	$ 31.06
Outstanding at the end of the period (in dollars per share)	$ 27.90
Options exercisable at the end of the period (in dollars per share)	$ 20.89
Aggregate Intrinsic Value
Outstanding at the end of the period (in dollars)	$ 22,593
Options exercisable at the end of the period (in dollars)	$ 20,823
Weighted Average Remaining Contractual Life
Outstanding at the end of the period	6 years 8 months 12 days
Options exercisable at the end of the period	4 years 9 months 18 days
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)	307
Vested (in shares)	(133)
Forfeited (including cancelled awards) (in shares)	(31)
Nonvested at the end of the period (in shares)	761
Weighted-Average Grant-Date Fair Value
Nonvested at the beginning of the period (in dollars per share)	$ 33.61
Granted (in dollars per share)	$ 32.64
Vested (in dollars per share)	$ 19.42
Forfeited (including cancelled awards) (in dollars per share)	$ 32.79
Nonvested at the end of the period (in dollars per share)	$ 35.73