Stock-based Compensation Share Based Compensation by Payment Award (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended			146 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	463,604	469,321		469,321
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 126.65	$ 132.33		$ 132.33
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	206,855
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 101.87
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(183,455)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$ 113.31
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(29,117)
Treasury Stock, Shares, Acquired				39,311,745
Treasury Stock, Value, Acquired, Cost Method				$ 1,600,000
Treasury Stock Acquired, Average Cost Per Share				$ 41.08
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period, Weighted Average Grant Date Fair Value	$ 126.09
Share-based Compensation	$ 21,279	$ 20,470	$ 20,526
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation		$ 3,020	$ 3,744
Share-based Compensation, Shares Authorized under Stock Options Plans, by Exercise Price Range, Range 1 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit		$ 0.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit		$ 0.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Range 2 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 0.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	0.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Range 3 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	0.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	0.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Range 4 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	0.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	0.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Range 5 [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	0.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 0.00
Restricted Stock Units (RSUs) [Member] | Director Stock Award Program [Member] | Restricted Share Award Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	8,616	4,536	7,616
Share-based Compensation	$ 900	$ 900	$ 700
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	21 months
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 1,100
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 900,000	$ 900,000	$ 1,000,000
Restricted Stock Units (RSUs) [Member] | Director Stock Award Program [Member] | Total Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	1,400,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	558,139
Restricted Stock Units (RSUs) [Member] | Employee stock award program [Member] | Restricted Share Award Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	91,784	80,983	94,620
Share-based Compensation	$ 10,400	$ 10,500	$ 10,300
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	45 months
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 30,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 8,900,000	$ 15,000,000	$ 12,300,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Intrinsic Value	$ 10,400,000	$ 10,400,000	$ 9,900,000
Employee Service Share-based Compensation, Tax Benefit from Compensation Expense	$ 200	$ 2,900	$ 3,000
Restricted Stock Units (RSUs) [Member] | Employee stock award program [Member] | Total Restricted Stock Award [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized	11,900,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,385,624
Restricted Stock Units (RSUs) [Member] | Performance Share Award Program 2013 Grant [Domain] | Employee stock award program [Member] | Performance Share Award Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period			79,660
Share-based Compensation	$ 3,200	$ 2,900	$ 3,400
Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Performance-Based Units, Vested and Expected to Vest [Table Text Block]			73660
Adjustments to Additional Paid in Capital, Income Tax Benefit from Share-based Compensation	$ 400
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 9,500,000
Restricted Stock Units (RSUs) [Member] | Performance Share Award Program 2014 Grant [Domain] | Employee stock award program [Member] | Performance Share Award Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period		53,548
Share-based Compensation	$ 3,000	$ 3,000
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	12 months
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 9,000,000
Restricted Stock Units (RSUs) [Member] | Performance Share Award Program 2015 Grant [Domain] | Employee stock award program [Member] | Performance Share Award Program [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	106,455
Share-based Compensation	$ 3,800
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	24 months
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 11,300,000