Share-Based Compensation Level 4 (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2019
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pretax employee share-based compensation expense included in net income	$ 15,029,000	$ 15,626,000	$ 14,788,000
Income tax benefit related to share-based compensation included in net income	$ 3,842,000	$ 3,998,000	$ 5,416,000
Stock Option Plan Exercise Range 1 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit	$ 0.00
Share-based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit	$ 10.00
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding				1,239,011
Share-based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Remaining Contractual Term	1 year 9 months 18 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price, Beginning Balance				$ 16.77
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable				1,239,011
Share-based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price				$ 16.77
Stock Option Plan Exercise Range 2 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit	$ 10.01
Share-based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit	$ 20.00
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding				4,096,760
Share-based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Remaining Contractual Term	4 years 2 months 12 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price, Beginning Balance				$ 24.99
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable				3,666,044
Share-based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price				$ 24.49
Stock Option Plan Exercise Range 3 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit	$ 20.00
Share-based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit	$ 30.00
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding				1,188,525
Share-based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Remaining Contractual Term	6 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 Payment Arrangement, Option, Exercise Price Range, Shares Exercisable				492,518
Share-based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price				$ 37.50
Stock Option Plan Exercise Range 4 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit	$ 30.00
Share-based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit	$ 40.00
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding				785,150
Share-based Payment Arrangement, Option, Exercise Price Range, Outstanding, 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				$ 42.63
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable				0
Share-based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price				$ 0
Stock Option Plan Exercise Range 5 [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Share-based Payment Arrangement, Option, Exercise Price Range, Lower Range Limit	$ 0.00
Share-based Payment Arrangement, Option, Exercise Price Range, Upper Range Limit	$ 40.00
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Outstanding				7,309,446
Share-based Payment Arrangement, Option, Exercise Price Range, Outstanding, Weighted Average Remaining Contractual Term	4 years 4 months 24 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price, Beginning Balance				$ 27.53
Share-based Payment Arrangement, Option, Exercise Price Range, Shares Exercisable				5,397,573
Share-based Payment Arrangement, Option, Exercise Price Range, Exercisable, Weighted Average Exercise Price				$ 23.90
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	1.70%	1.80%	2.00%
Expected volatility	19.80%	18.50%	19.00%
Risk-free interest rate	2.50%	2.40%	1.60%
Expected holding period	4 years	4 years	4 years
Total pretax employee share-based compensation expense included in net income	$ 6,314,000	$ 6,648,000	$ 6,909,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding at beginning of period	8,917,943
Options outstanding at beginning of period, weighted average exercise price	$ 23.40
Granted	785,150
Granted, Weighted Average Exercise Price	$ 42.63
Exercised	(2,393,647)
Exercised, Weighted Average Exercise Price	$ 17.10
Options outstanding at end of period	7,309,446	8,917,943
Options outstanding at end of period, weighted average exercise price	$ 27.53	$ 23.40
Options exercisable at December 31, 2011	7,309,446	8,917,943		7,309,446
Options exercisable at December 31, 2011, Weighted Average Exercise Price	$ 27.53	$ 23.40		$ 27.53
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number				5,397,573
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price				$ 23.90
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	$ 6,000,000	$ 6,063,000	$ 5,564,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested restricted shares at beginning of period	389,245
Nonvested restricted shares at beginning of period, weighted average grant date fair value	$ 31.67
Granted	125,546
Granted, Weighted Average Grant Date Fair Value	$ 42.73	$ 37.50	$ 29.28
Vested	(226,726)
Vested, Weighted Average Grant Date Fair Value	$ 29.63
Nonvested restricted shares at end of period	288,065	389,245
Nonvested restricted shares at end of period, weighted average grant date fair value	$ 38.09	$ 31.67
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	$ 6,718,000	$ 5,702,000	$ 5,463,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Vested	3,724,000	3,578,000	4,454,000
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	$ 2,715,000	$ 2,862,000	$ 2,052,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested restricted shares at beginning of period	175,301
Nonvested restricted shares at beginning of period, weighted average grant date fair value	$ 31.17
Granted	72,067
Granted, Weighted Average Grant Date Fair Value	$ 40.91	$ 35.89	$ 27.94
Vested	(95,459)
Vested, Weighted Average Grant Date Fair Value	$ 29.62
Nonvested restricted shares at end of period	151,452	175,301
Nonvested restricted shares at end of period, weighted average grant date fair value	$ 36.79	$ 31.17
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value	$ 2,827,000	$ 1,946,000	$ 1,239,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(457)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 27.94
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Aggregate Intrinsic Value, Vested	$ 1,432,000	$ 970,000	$ 558,000