Share-Based Compensation Level 4 (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pretax employee share-based compensation expense included in net income	$ 15,626,000	$ 14,788,000	$ 14,056,000
Income tax benefit related to share-based compensation included in net income	$ 3,998,000	$ 5,416,000	$ 6,427,000
Stock Option Plan Exercise Range 1 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
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	$ 10.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options				3,127
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	1 month 6 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price, Beginning Balance				$ 9.09
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options				3,127
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price				$ 9.09
Stock Option Plan Exercise Range 2 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 10.01
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 20.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options				2,878,785
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	2 years 5 months 6 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price, Beginning Balance				$ 15.38
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options				2,878,785
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price				$ 15.38
Stock Option Plan Exercise Range 3 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 20.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 30.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options				4,836,611
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	5 years 1 month 12 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price, Beginning Balance				$ 24.68
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options				3,263,385
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price				$ 23.73
Stock Option Plan Exercise Range 4 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 30.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 40.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options				1,199,420
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	7 years 1 month 6 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price, Beginning Balance				$ 37.50
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options				0
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price				$ 0.00
Stock Option Plan Exercise Range 5 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
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	$ 40.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options				8,917,943
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	4 years 6 months 6 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price, Beginning Balance				$ 23.40
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options				6,145,297
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price				$ 19.81
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	1.80%	2.00%	2.00%
Expected volatility	18.50%	19.00%	19.70%
Risk-free interest rate	2.40%	1.60%	1.00%
Expected holding period	4 years	4 years	4 years
Total pretax employee share-based compensation expense included in net income	$ 6,648,000	$ 6,909,000	$ 7,633,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding at beginning of period	9,520,299
Options outstanding at beginning of period, weighted average exercise price	$ 19.77
Granted	1,199,420
Granted, Weighted Average Exercise Price	$ 37.50
Exercised	(1,801,776)
Exercised, Weighted Average Exercise Price	$ 13.61
Options outstanding at end of period	8,917,943	9,520,299
Options outstanding at end of period, weighted average exercise price	$ 23.40	$ 19.77
Options exercisable at December 31, 2011	9,520,299	9,520,299		8,917,943
Options exercisable at December 31, 2011, Weighted Average Exercise Price	$ 19.77	$ 19.77		$ 23.40
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number				6,145,297
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price				$ 19.81
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pretax employee share-based compensation expense included in net income	$ 6,063,000	$ 5,564,000	$ 5,640,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested restricted shares at beginning of period	441,811
Nonvested restricted shares at beginning of period, weighted average grant date fair value	$ 25.70
Granted	177,944
Granted, Weighted Average Grant Date Fair Value	$ 37.50	$ 29.28	$ 22.28
Vested	(230,510)
Vested, Weighted Average Grant Date Fair Value	$ 24.74
Nonvested restricted shares at end of period	389,245	441,811
Nonvested restricted shares at end of period, weighted average grant date fair value	$ 31.67	$ 25.70
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	$ 5,702,000	$ 5,463,000	$ 5,682,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Vested	3,578,000	4,454,000	3,214,000
Restricted Stock Units (RSUs) [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pretax employee share-based compensation expense included in net income	$ 2,862,000	$ 2,052,000	$ 820,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested restricted shares at beginning of period	167,030
Nonvested restricted shares at beginning of period, weighted average grant date fair value	$ 26.92
Granted	84,604
Granted, Weighted Average Grant Date Fair Value	$ 35.89	$ 27.94	$ 25.72
Vested	(72,437)
Vested, Weighted Average Grant Date Fair Value	$ 26.86
Nonvested restricted shares at end of period	175,301	167,030
Nonvested restricted shares at end of period, weighted average grant date fair value	$ 31.17	$ 26.92
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	$ 1,946,000	$ 1,238,700	$ 50,200
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(3,896)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 31.63
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Vested	$ 970,000	$ 558,000	$ 5,000