Equity Incentive Compensation Plans (Restricted Stock Units and Performance Share Program) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Restricted Stock Units
Other than stock options activity
Outstanding at the beginning of the period (in shares)	915,022	[1],[2]	857,360	[1],[2]	1,107,293
Granted (in shares)	164,112		159,333		34,529
Issued (in shares)	(79,068)		(62,127)		(246,633)
Canceled/expired (in shares)	(18,189)		(39,544)		(37,829)
Outstanding at the end of the period (in shares)	981,877	[1],[2]	915,022	[1],[2]	857,360	[1],[2]
Weighted-average intrinsic value at grant-date
Outstanding at the beginning of the period (in dollars per share)	$ 23.88	[1],[2]	$ 19.67	[1],[2]	$ 22.14
Granted (in dollars per share)	$ 50.60		$ 47.98		$ 30.94
Issued (in dollars per share)	$ 33.10		$ 26.18		$ 28.98
Canceled/expired (in dollars per share)	$ 41.50		$ 25.12		$ 22.20
Outstanding at the end of the period (in dollars per share)	$ 26.72		$ 23.88	[1],[2]	$ 19.67	[1],[2]
Vest Date Fair Value - Issued (in dollars)	$ 3,401		$ 2,588		$ 7,813
Performance Based Restricted Stock Units
Other than stock options activity
Outstanding at the beginning of the period (in shares)	162,849		103,794		0
Granted (in shares)	59,738		65,620		103,794
Issued (in shares)	0		0		0
Canceled/expired (in shares)	0		(6,565)		0
Outstanding at the end of the period (in shares)	222,587		162,849		103,794
Weighted-average intrinsic value at grant-date
Outstanding at the beginning of the period (in dollars per share)	$ 39.00		$ 31.20		$ 0.00
Granted (in dollars per share)	$ 63.69		$ 51.86		$ 31.20
Issued (in dollars per share)	$ 0.00		$ 0.00		$ 0.00
Canceled/expired (in dollars per share)	$ 0.00		$ 44.20		$ 0.00
Outstanding at the end of the period (in dollars per share)	$ 45.79		$ 39.00		$ 31.20
Vest Date Fair Value - Issued (in dollars)	$ 0		$ 0		$ 0

[1] The balance outstanding includes RSUs granted to non-employee directors that are 100% vested at the date of grant but are subject to deferral elections delaying the date on which the corresponding shares of Common Stock are issued. For the years ended December 31, 2012, 2011 and 2010, 43,554, 30,544 and 10,522 RSUs have vested, but the corresponding shares of Common Stock have not been issued.

[2] The balance outstanding includes RSUs granted to executive officers and other officers that have vested in accordance with the RSU agreement, but are subject to a deferral election before the corresponding shares of Common Stock are issued. For the years ended December 31, 2012, 2011 and 2010, 614,996, 483,908 and 289,335 RSUs have vested, but the corresponding shares of Common Stock have not been issued.