Share-Based Compensation Level 4 (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total pretax employee share-based compensation expense included in net income	$ 14,056	$ 13,843	$ 13,127
Income tax benefit related to share-based compensation included in net income	$ 6,427	$ 5,068	$ 7,368
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Exercised	0	(122,000)	(761,000)
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options				10,775,136
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	4 years 7 months 6 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price, Beginning Balance				$ 16.49
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options				6,938,591
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price				$ 13.69
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	$ 5.00
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				2,032,763
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	1 year 8 months 12 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price, Beginning Balance				$ 8.42
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options				2,032,763
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price				$ 8.42
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	$ 15.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options				1,361,450
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	3 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				$ 11.18
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options				1,361,450
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price				$ 11.18
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	$ 15.01
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				3,548,915
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	4 years 8 months 12 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price, Beginning Balance				$ 16.50
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options				2,801,293
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price				$ 16.26
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	$ 20.01
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 25.00
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Outstanding Options				3,832,008
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Remaining Contractual Term	6 years 7 months 6 days
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Outstanding Options, Weighted Average Exercise Price, Beginning Balance				$ 22.65
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Number of Exercisable Options				743,085
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Exercisable Options, Weighted Average Exercise Price				$ 22.97
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Dividend yield	2.00%	1.80%	1.80%
Expected volatility	19.70%	23.30%	27.10%
Risk-free interest rate	1.00%	1.30%	1.10%
Expected holding period	4 years	4 years	4 years
Total pretax employee share-based compensation expense included in net income	$ 7,600	$ 7,900	$ 7,500
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding at beginning of period	11,047,920
Options outstanding at beginning of period, weighted average exercise price	$ 13.98
Granted	1,863,700
Granted, Weighted Average Exercise Price	$ 22.28
Exercised	(2,108,212)
Exercised, Weighted Average Exercise Price	$ 8.38
Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures in Period	(28,272)
Cancelled, Weighted Average Exercise Price	$ 20.98
Options outstanding at end of period	10,775,136	11,047,920
Options outstanding at end of period, weighted average exercise price	$ 16.49	$ 13.98
Options exercisable at December 31, 2011	11,047,920	11,047,920		10,775,136
Options exercisable at December 31, 2011, Weighted Average Exercise Price	$ 13.98	$ 13.98		$ 16.49
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number				6,938,591
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price				$ 13.69
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	$ 5,600	$ 5,900	$ 5,700
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested restricted shares at beginning of period	573,739
Nonvested restricted shares at beginning of period, weighted average grant date fair value	$ 19.32
Granted	241,510
Granted, Weighted Average Grant Date Fair Value	$ 22.28
Vested	(313,247)
Vested, Weighted Average Grant Date Fair Value	$ 18.14
Nonvested restricted shares at end of period	500,744	573,739
Nonvested restricted shares at end of period, weighted average grant date fair value	$ 21.48	$ 19.32
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(1,258)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 20.85
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	$ 800
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested [Roll Forward]
Nonvested restricted shares at beginning of period	0
Nonvested restricted shares at beginning of period, weighted average grant date fair value	$ 0.00
Granted	130,660
Granted, Weighted Average Grant Date Fair Value	$ 25.72
Vested	(1,950)
Vested, Weighted Average Grant Date Fair Value	$ 25.72
Nonvested restricted shares at end of period	123,510	0
Nonvested restricted shares at end of period, weighted average grant date fair value	$ 25.72	$ 0.00
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(5,200)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value	$ 25.72