Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Tax Credit Carryforward [Line Items]
Federal general business credit carryforwards	$ 200,000	$ 200,000
Limit on annual basis	1,200,000
Valuation allowance on equity investment	600,000
Valuation allowance	373,000	0
Accrued interest (less than)	100,000	100,000
Net expense for one-time transition tax	800,000
Net expense for revaluation of deferred tax assets and liabilities	800,000
General Business Tax Credit Carryforward
Tax Credit Carryforward [Line Items]
Federal and state net operating loss carryforwards	$ 400,000	$ 1,600,000