Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Income Taxes
Income tax provision	$ (328)	$ 508	$ 943	$ 7,036
Decrease in income tax	800		6,100
Decrease in income tax due to decrease in pretax income	800
Decrease in pretax income	9,000		36,200
Tax benefit relating to the 2017 Tax Cut and Jobs Act		$ 1,400
Deferred tax assets	71,121		71,121		$ 71,939
Deferred tax assets valuation allowance	$ 7,700		$ 7,700		$ 6,800