Equity Incentive Compensation Plans (Restricted Stock Units and Performance Share Program) (Details 3) (USD $)	0 Months Ended		6 Months Ended
	Jun. 30, 2013		Jun. 30, 2013
Weighted average grant date fair value
Total unrecognized compensation cost	$ 2,000,000		$ 2,000,000
Period of recognition of unrecognized compensation cost (in years)	2 years 9 months
Restricted Stock Units
Other than stock options activity
Outstanding at the beginning of the period (in shares)			981,877
Granted (in shares)			264,033
Issued (in shares)			(176,724)
Canceled/expired (in shares)			(13,707)
Outstanding at the end of the period (in shares)	1,055,479	[1],[2]	1,055,479	[1],[2]
Weighted average grant date fair value
Outstanding at the beginning of the period (in dollars per share)			$ 26.72
Granted (in dollars per share)			$ 45.27
Issued (in dollars per share)			$ 24.68
Canceled/expired (in dollars per share)			$ 43.85
Outstanding at the end of the period (in dollars per share)	$ 32.02		$ 32.02
Vest date fair value - issued (in dollars)			6,884,000
Total unrecognized compensation cost	18,900,000		18,900,000
Period of recognition of unrecognized compensation cost (in years)	3 years 9 months
Performance-Based RSUs
Other than stock options activity
Outstanding at the beginning of the period (in shares)			222,587	[3]
Granted (in shares)			0
Issued (in shares)			(64,922)
Canceled/expired (in shares)			(34,742)
Outstanding at the end of the period (in shares)	122,923	[3]	122,923	[3]
Weighted average grant date fair value
Outstanding at the beginning of the period (in dollars per share)			$ 45.79
Granted (in dollars per share)			$ 0.00
Issued (in dollars per share)			$ 32.75
Canceled/expired (in dollars per share)			$ 28.32
Outstanding at the end of the period (in dollars per share)	$ 57.61		$ 57.61
Vest date fair value - issued (in dollars)			2,990,000
Total unrecognized compensation cost	$ 1,500,000		$ 1,500,000
Period of recognition of unrecognized compensation cost (in years)	1 year 6 months
Nonemployee Directors | Restricted Stock Units
Equity Incentive Compensation Plans
Fully vested shares outstanding subject to non-employee director deferral election (in shares)	58,036		58,036
Percentage of stock units vested at date of grant (as a percent)	100.00%		100.00%
Executive Officer | Restricted Stock Units
Equity Incentive Compensation Plans
Fully vested shares outstanding subject to deferral election by executive officers or other officers (in shares)	510,967		510,967

[1] (1)The balance outstanding includes 58,036 RSUs granted to non-employee directors that are 100% vested at date of grant, but are subject to deferral elections delaying the date on which the corresponding shares are issued.

[2] (2)The balance outstanding includes 510,967 RSUs granted to executive officers and other officers that have vested in accordance with the RSU agreement but are subject to deferral elections delaying the date on which the corresponding shares are issued.

[3] eflects the maximum number of performance shares that can be issued.