Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2015

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
	2015				2014				2013
	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	1,406,550		$	6.21	1,477,762		$	5.83	1,463,272		$	5.97
Granted	390,200		9.61		467,567		7.52		627,488		5.73
Converted	(498,491	)	5.97		(404,179	)	6.49		(526,848	)	5.72
Expired	(126,800	)	5.52		(116,800	)	5.70		(68,950	)	8.25
Forfeited	(13,800	)	7.36		(17,800	)	6.26		(17,200	)	7.07
Outstanding at end of period	1,157,659		$	7.52	1,406,550		$	6.21	1,477,762		$	5.83
Vested	511,109		$	6.03	555,927		$	5.73	506,644		$	4.47

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 2015, 2014 and 2013 using daily stock prices and using the following variables:

	2015	2014	2013
Risk-free interest rate	0.9%	0.8%	0.4%
Volatility	41.5%	48.9%	61.0%