Net Income per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended									12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	[1]	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Net Income per Share [Abstract]
Net income	$ 544	$ 5,144	$ 6,853	$ 7,591	$ 9,393	$ (5,768)		$ 3,068	$ 3,526	$ 20,132	[2]	$ 10,219	[2]	$ 22,423	[2]
Less: earnings allocated to RSUs										(450)		(375)
Net income (loss) available to common shareholders										$ 19,682		$ 9,844
Weighted average number of common shares outstanding										29,031		28,776		28,595
Basic and diluted										$ 0.68		$ 0.34		$ 0.78

[1] Includes $8.9 million related to Vectren deal costs.

[2] *There is no material difference between net income and comprehensive income.