Stock-Based Compensation Stock Option Summary (Details) (Employee Stock Option [Member], USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014		Dec. 31, 2013
[Line Items]
Outstanding, beginning balance, Number	1,123				1,180
Outstanding, beginning balance, Weighted Average Exercise Price Per Share	$ 51.90				$ 54.79
Outstanding, beginning balance, Weighted Average Remaining Contractual Term	5 years 5 months 26 days		4 years 5 months 0 days		5 years 0 months 0 days		4 years 7 months 22 days
Outstanding, beginning balance, Aggregate Intrinsic Value	$ 1,676	[1]			$ 1,300	[1]
Options granted, number	204				147
Granted, Weighted Average Exercise Price Per Share	$ 35.29				$ 35.19
Granted, Weighted Average Grant Date Fair Value	$ 12.15				$ 13.64
Exercised, Number	(2)				(5)
Exercised, Weighted Average Exercise Price Per Share	$ 26.65				$ 35.71
Exercised, Aggregate Intrinsic Value	17	[1]			25	[1]
Expired, Number	(1)				0
Expired, Weighted Average Exercise Price Per Share	$ 37.40				$ 0.00
Outstanding, ending balance, Number	1,324		1,123		1,322		1,180
Outstanding, ending balance, Weighted Average Exercise Price Per Share	$ 49.39		$ 51.90		$ 52.68		$ 54.79
Outstanding, ending balance, Weighted Average Remaining Contractual Term	5 years 5 months 26 days		4 years 5 months 0 days		5 years 0 months 0 days		4 years 7 months 22 days
Outstanding, ending balance, Aggregate Intrinsic Value	451	[1]	1,676	[1]	613	[1]	1,300	[1]
Exercisable, Number	922
Exercisable, Weighted Average Exercise Price Per Share	$ 54.84
Exercisable, Weighted Average Remaining Contractual Term	3 years 10 months 15 days
Exercisable, Aggregate Intrinsic Value	73	[1]
Expected to Vest [Member]
[Line Items]
Outstanding, beginning balance, Weighted Average Remaining Contractual Term	9 years 2 months 0 days
Outstanding, ending balance, Number	382
Outstanding, ending balance, Weighted Average Exercise Price Per Share	$ 36.91
Outstanding, ending balance, Weighted Average Remaining Contractual Term	9 years 2 months 0 days
Outstanding, ending balance, Aggregate Intrinsic Value	$ 357	[1]

[1] The aggregate intrinsic value of outstanding stock options represents amounts that would have been received by the optionees had all in- the-money options been exercised on that date. Specifically, it is the amount by which the market value of our stock exceeded the exercise price of the outstanding in-the-money options before applicable income taxes, based on our closing stock price on the last business day of the period. The aggregate intrinsic value of stock options exercised during the period is calculated based on our stock price at the date of exercise.