Income Taxes (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Income Taxes
U.S. statutory income tax rate (as a percent)	21.00%	35.00%
Reduction in the deferred tax liability		$ 373,000
Deferred tax liability adjustment	$ 536,000