Income Taxes - Income Tax Contingencies (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations		$ 3,005	$ 2,693	$ 2,235
Accrued interest reversed		200	200	100
Accrued interest and penalties related to unrecognized tax benefits		600	500
Interest and penalties recorded		100	200	100
Forecast
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations	$ 3,600
Deferred tax assets
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations		600	1,000	700
Deferred tax assets | Forecast
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations	700
Income Tax Expense
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations		$ 2,400	$ 2,000	$ 1,500
Income Tax Expense | Forecast
Income tax contingency disclosures
Unrecognized tax benefits: Changes due to lapses of statutes of limitations	$ 2,900