Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions

The following summarizes the significant assumptions used to determine the fair value of performance shares and related compensation expense as well as the resulting estimated fair value of performance shares granted:

	2016		2015
Risk-free interest rate	0.85	%	1.06	%
Expected life, in years	3		3
Expected volatility	17.1% to 22.1%		14.2% to 19.0%
Dividend yield	3.4	%	3.5	%

Schedule of Nonvested Share Activity

A summary of nonvested shares as of and changes during the year ended December 31, 2016, are as follows:

	Performance Unit Awards
	Shares		Weighted-Average Grant-Date Fair Value
Beginning nonvested grants	187,572		$	40.39
Granted	88,107		50.32
Vested	(90,417	)	38.33
Forfeited	(10,005	)	42.12
Remaining nonvested grants	175,257		$	46.35

Share-based Compensation Arrangement by Share-based Payment Award

Schedule of Nonvested Restricted Stock Units Activity

A summary of nonvested shares as of and changes during the year ended December 31, 2016, are as follows:

	Shares		Weighted-Average Grant-Date Fair Value
Beginning nonvested grants	57,313		$	37.76
Granted	15,708		45.78
Vested	(8,112	)	28.00
Forfeited	(2,318	)	35.11
Remaining nonvested grants	62,591		$	41.14