Equity Incentive Compensation Plans (Restricted Stock Units and Performance Share Program) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Restricted Stock Units
Other than stock options activity
Outstanding at the beginning of the period (in shares)	915,022
Granted (in shares)	143,601
Issued (in shares)	(49,706)
Canceled/expired (in shares)	(4,490)
Outstanding at the end of the period (in shares)	1,004,427
Weighted average grant date fair value
Outstanding at the beginning of the period (in dollars per share)	$ 23.88
Granted (in dollars per share)	$ 52.08
Issued (in dollars per share)	$ 43.23
Canceled/expired (in dollars per share)	$ 25.13
Outstanding at the end of the period (in dollars per share)	$ 26.74
Vest date fair value - issued (in dollars)	$ 2,406
Performance-Based RSUs
Other than stock options activity
Outstanding at the beginning of the period (in shares)	162,849	[1]
Granted (in shares)	59,738	[1]
Issued (in shares)	0	[1]
Canceled/expired (in shares)	0	[1]
Outstanding at the end of the period (in shares)	222,587	[1]
Weighted average grant date fair value
Outstanding at the beginning of the period (in dollars per share)	$ 39.00
Granted (in dollars per share)	$ 63.69
Issued (in dollars per share)	$ 0.00
Canceled/expired (in dollars per share)	$ 0.00
Outstanding at the end of the period (in dollars per share)	$ 45.79
Vest date fair value - issued (in dollars)	$ 0

[1] Reflects the maximum number of performance shares that can be issued.