Income Taxes - Net Deferred Tax Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Taxes
Statutory Federal income tax rate (as a percent)	21.00%	35.00%	35.00%
Net deferred tax assets
Net deferred tax assets		$ 7,103,000
Valuation allowance for deferred tax assets	$ 0