Quarterly report pursuant to Section 13 or 15(d)

Stock-Based Compensation (Schedule of Changes in the Number of Deferred Stock Shares Under the Incentive Plan) (Details)

v3.8.0.1
Stock-Based Compensation (Schedule of Changes in the Number of Deferred Stock Shares Under the Incentive Plan) (Details) - Performance Units [Member]
3 Months Ended
Mar. 31, 2018
$ / shares
shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]  
Shares, Outstanding - December 31, 2017 | shares 190,524
Shares, Granted | shares 163,002
Shares, Vested | shares (29,708)
Shares, Forfeited | shares (9,424)
Shares, Outstanding - March 31, 2018 | shares 314,394
Weighted Average Grant Date Fair Value, Outstanding - December 31, 2017 | $ / shares $ 6.60
Weighted Average Grant Date Fair Value, Granted | $ / shares 3.56
Weighted Average Grant Date Fair Value, Vested | $ / shares 10.51
Weighted Average Grant Date Fair Value, Forfeited | $ / shares 11.48
Weighted Average Grant Date Fair Value, Outstanding - March 31, 2018 | $ / shares $ 4.51