Long-Term Equity Compensation (Summary of Stock Options) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Long Term Equity Compensation [Abstract]
Oustanding beginning balance, Number of Options	5,623,818
Granted, Number of Options	0	661,950	1,076,179
Exercised, Number of Options	(659,017)
Forfeited or expired, Number of Options	(683,068)
Oustanding ending balance, Number of Options	4,281,733	5,623,818
Outstanding beginning balance, Weighted Average Exercise Price	$ 29.29
Granted, Weighted Average Exercise Price	$ 0.00
Exercsied, Weighted Average Exercise Price	$ 25.71
Forfeited or expired, Weighted Average Exercise Price	$ 27.10
Outstanding ending balance, Weighted Average Exercise Price	$ 30.19	$ 29.29
Outstanding balance, Weighted Average Remaining Contractual Term (Years)	3 years 1 month 24 days
Oustanding balance, Agregate Intrinsic Value	$ 3,147,027
Vested or expected to vest, Number of Options	4,127,149
Vested or expected to vest, Weighted Average Exercise Price	$ 30.38
Vested or expected to vest, Weighted Average Remaining Contractual Term (Years)	3 years 1 month 6 days
Vested or expected to vest, Aggregate Intrinsic Value	3,004,470
Exercisable, Number of Options	2,955,047
Exercisable, Weighted Average Exercise Price	$ 32.32
Exercisable, Weighted Average Remaining Contractual Term (Years)	2 years 6 months 21 days
Exercisable, Aggregate Intrinsic Value	$ 1,999,078