Schedule V. Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allowance for bad debts
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	$ 867	$ 618	$ 896
Charged to costs and expenses	388	249	0
Deductions	0	0	278
Balance at end of period	1,255	867	618
Deferred tax asset valuation allowance
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at beginning of period	1,265	1,813	2,361
Charged to costs and expenses	0	0	0
Deductions	547	548	548
Balance at end of period	$ 718	$ 1,265	$ 1,813