Stock-Based Compensation Stock Option Summary (Details) - Employee Stock Option [Member] - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended
		Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
[Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term		5 years 5 months 14 days		5 years 5 months 14 days
Outstanding, beginning balance, Number		1,180		1,123
Outstanding, beginning balance, Weighted Average Exercise Price Per Share		$ 48.31		$ 51.90
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term		5 years 6 months		5 years 6 months	4 years 4 months 22 days
Outstanding, beginning balance, Aggregate Intrinsic Value	[1]			$ 1,676
Options granted, number		185		204
Granted, Weighted Average Exercise Price Per Share		$ 40.04		$ 35.29
Granted, Weighted Average Grant Date Fair Value		$ 13.15		$ 12.15
Exercised, Number		(12)		(2)
Exercised, Weighted Average Exercise Price Per Share		$ 35.29		$ 26.65
Exercised, Aggregate Intrinsic Value	[1]	$ 73		$ 17
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Number of Shares		(35)
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested Options Forfeited, Weighted Average Grant Date Fair Value		$ 35.29
Expired, Number		(1)		(1)
Expired, Weighted Average Exercise Price Per Share		$ 48.51		$ 37.40
Outstanding, ending balance, Number		1,317	1,180	1,324	1,123
Outstanding, ending balance, Weighted Average Exercise Price Per Share		$ 47.61	$ 48.31	$ 49.39	$ 51.90
Outstanding, ending balance, Aggregate Intrinsic Value	[1]	$ 2,859		$ 451	$ 1,676
Exercisable, Number		892
Exercisable, Weighted Average Exercise Price Per Share		$ 52.46
Exercisable, Weighted Average Remaining Contractual Term		3 years 7 months
Exercisable, Aggregate Intrinsic Value	[1]	$ 1,040
Expected to Vest [Member]
[Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term		9 years 5 months
Outstanding, ending balance, Number		404
Outstanding, ending balance, Weighted Average Exercise Price Per Share		$ 37.42
Outstanding, ending balance, Aggregate Intrinsic Value	[1]	$ 1,736

[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.