Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Income Tax Disclosure [Abstract]
U.S. Federal tax rate			35.00%
Income tax expense (benefit)	$ 2,389	$ 1,104	$ 7,505	$ 1,486
Effective tax rate	47.70%	24.80%	(38.20%)	32.00%
Increase rate related to reversal of previously recorded railroad track maintenance	6.70%
Goodwill write-off	$ 0	$ 0	$ 42,000	$ 0