Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2014

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:

	2014		2013
Risk-free interest rate	0.67	%	0.44	%
Expected life, in years	3		3
Expected volatility	15.5% to 23.3%		16.3% to 25.4%
Dividend yield	3.3	%	3.9	%

Schedule of Nonvested Share Activity

A summary of nonvested shares as of and changes during the year ended December 31, 2014, are as follows:

	Performance Share Awards
	Shares		Weighted-Average Grant-Date Fair Value
Beginning nonvested grants	173,646		$	29.14
Granted	96,193		38.33
Vested	(84,652	)	25.19
Forfeited	(4,615	)	33.55
Remaining nonvested grants	180,572		$	35.77

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, 2014, are as follows:

	Shares	Weighted-Average Grant-Date Fair Value
Beginning nonvested grants	26,628	$	30.24
Granted	15,092	43.79
Vested	—	—
Forfeited	—	—
Remaining nonvested grants	41,720	$	35.14