Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2016

Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]

Summary of Company's Option Activity

A summary of the Company’s option activity and related information for the three years ended December 31, 2016 is as follows:

	Number of options			Weighted- average price		Weighted- average remaining contractual term (in years)		Aggregate intrinsic value (in millions)
Balance at December 31, 2013		1,772,062		$	24.68
Options granted		203,600			32.79
Options exercised	(612,682)				21.55
Options cancelled/forfeited/expired		(19,220	)		30.35
Balance at December 31, 2014		1,343,760			27.25
Options granted		456,200			31.69
Options exercised		(270,650	)		19.81
Options cancelled/forfeited/expired		(118,660	)		29.58
Balance at December 31, 2015		1,410,650			29.91
Options granted		881,800			25.26
Options exercised		(368,085	)		27.34
Options cancelled/forfeited/expired		(339,930	)		28.62
Balance at December 31, 2016		1,584,435		$	28.14		6.20	$	17.5
Exercisable at December 31, 2016		354,165		$	30.85		4.70	$	3.0
Expected to vest after December 31, 2016		1,107,243		$	27.36		6.63	$	13.1

Options Outstanding and Options Exercisable by Exercise Price with Weighted-Average Remaining Contractual Life for Options Outstanding and Weighted-Average Exercise Price

The following table indicates the options outstanding and options exercisable by exercise price with the weighted-average remaining contractual life for the options outstanding and the weighted-average exercise price at December 31, 2016:

	Options Outstanding						Options Exercisable
Exercise price	Number outstanding at December31, 2016		Weighted- average remaining contractual life (Years)		Weighted- average grant date value		Number exercisable at December 31, 2016		Weighted- average grant date value
$20 – 25		751,500		6.98	$	24.60		3,780	$	23.84
$25 – 30		171,920		4.08	$	28.59		118,500	$	28.93
$30 – 35		651,355		5.85	$	32.06		231,005	$	32.12
$35 – 40		9,600		6.41	$	38.43		880	$	36.62
$20 – 40		1,584,375		6.20	$	28.14		354,165	$	30.78

Schedule of Weighted-Average Assumptions Used to Determine Fair Value of Option Granted

The fair value of each option granted was estimated on the date of grant using the Black-Scholes option-pricing model using the following weighted-average assumptions:

	Year Ended December 31,
	2016			2015			2014
Expected term (in years)		5.0			5.0			5.0
Expected volatility		28.7	%		31.1	%		40.5	%
Expected dividend yields		4.1	%		3.2	%		3.0	%
Risk-free interest rates		1.2	%		1.6	%		1.5	%

Summary of Company's Restricted Stock Units Activity

The following table summarizes the activity of the Company’s RSUs, which includes service-based and performance-based awards, for the three years ended December 31, 2016:

				Weighted-		Aggregate
				average		intrinsic
	Number			grant Date		value
	of shares			fair value		(in millions)
Balance at December 31, 2013		320,980		$	28.47
RSUs granted		118,864			30.85
RSUs vested		(120,721	)		27.30
RSUs cancelled/forfeited/expired		(7,540	)		30.34
Balance at December 31, 2014		311,583			29.78
RSUs granted		79,300			31.86
RSUs vested		(89,915	)		27.97
RSUs cancelled/forfeited/expired		(80,320	)		31.35
Balance at December 31, 2015		220,648			30.70
RSUs granted		31,900			25.75
RSUs vested		(59,008	)		29.69
RSUs cancelled/forfeited/expired		(68,300	)		29.33
Balance at December 31, 2016		125,240		$	30.66	$	4.9