Income Taxes (Details) - USD ($)	3 Months Ended			6 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Taxes [Abstract]
Income tax expense (benefit)	$ 1,181,000	$ 3,598,000	$ 4,434,000	$ (266,000)	$ 8,032,000
Effective income tax rate	25.20%	39.10%		11.80%	37.50%
Corporate tax rate				21.00%		35.00%
Years subject to examination				2018 2017 2016 2015