Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

Share-based Compensation [Abstract]

Target grants performance share

Target grants of performance shares outstanding at December 31, 2016, were as follows:

Grant Date	Performance Period	Target Grant of Shares
February 2014	2014-2016	136,901
February 2015	2015-2017	200,112
June 2015	2015-2017	14,441
February 2016	2016-2018	310,583
March 2016	2016-2018	2,151

Schedule of share-based payment award, performance shares, valuation assumptions

Assumptions used for grants of performance shares issued in 2016, 2015 and 2014 were:

				2016						2015						2014
Weighted average grant-date fair value					$14.60						$18.98						$41.13
Blended volatility range	29.25	%	–	32.51		%	22.86	%	–	24.61		%	18.94	%	–	20.43		%
Risk-free interest rate range	.47	%	–	.92		%	.05	%	–	1.07		%	.03	%	–	.74		%
Weighted average discounted dividends per share					$1.56						$1.57						$2.15

Summary of the status of the performance share awards

A summary of the status of the performance share awards for the year ended December 31, 2016, was as follows:

	Number of Shares	Weighted Average Grant-Date Fair Value
Nonvested at beginning of period	565,896	$	27.90
Granted	324,205	14.60
Less:
Vested	58,401	29.01
Forfeited	167,512	27.30
Nonvested at end of period	664,188	$	21.47