Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

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

Schedule of Share-based Compensation, Equity Instruments Other Than Options, Activity

The table below summarizes award activity.

	Year Ended December 31
	2016				2015				2014
	Number of Awards		Weighted average grant-date fair value		Number of Awards		Weighted average grant-date fair value		Number of Awards		Weighted average grant-date fair value
Outstanding at beginning of period	1,157,659		$	7.52	1,406,550		$	6.21	1,477,762		$	5.83
Granted	314,060		15.47		390,200		9.61		467,567		7.52
Converted	(329,200	)	7.32		(498,491	)	5.97		(404,179	)	6.49
Expired	(92,750	)	7.44		(126,800	)	5.52		(116,800	)	5.70
Forfeited	(9,200	)	10.23		(13,800	)	7.36		(17,800	)	6.26
Outstanding at end of period	1,040,569		$	9.97	1,157,659		$	7.52	1,406,550		$	6.21
Vested	472,294		$	6.60	511,109		$	6.03	555,927		$	5.73

Schedule of Share-based Payment Award, Equity Instruments Other Than Options, Valuation Assumptions

The market condition awards were valued using a Monte Carlo simulation technique based on volatility over three years for the awards granted in 2016, 2015 and 2014 using daily stock prices and using the following variables:

	2016	2015	2014
Risk-free interest rate	1.1%	0.9%	0.8%
Volatility	36.9%	41.5%	48.9%