Schedule V. Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allowance for bad debts
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 1,255	$ 1,255	$ 867
Charged to costs and expenses	0	0	388
Deductions	470	0	0
Balance at end of period	785	1,255	1,255
Deferred tax asset valuation allowance
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	329	718	1,265
Charged to costs and expenses	0	0	0
Deductions	329	389	547
Balance at end of period	$ 0	$ 329	$ 718