Schedule V - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Movement in valuation and qualifying accounts
Balance at Beginning of Period	$ 482	$ 414	$ 435
Charged to Costs and Expenses	1,358	1,338	1,203
Deductions	1,262	1,270	1,224
Balance at End of Period	$ 578	$ 482	$ 414