Unpaid Losses and Loss Adjustment Expenses - Changes in the Liability for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Gross reserves - beginning of period	$ 62,135	$ 38,488	$ 54,651	$ 35,422
Less: reinsurance recoverables on unpaid losses	9,125	5,015	6,658	5,405
Net reserves - beginning of period	53,010	33,473	47,993	30,017
Add: incurred losses and LAE, net of reinsurance:
Current period	12,397	12,034	25,051	23,146
Prior period	4,277	1,507	7,356	3,094
Total net incurred losses and LAE	16,674	13,541	32,407	26,240
Deduct: loss and LAE payments, net of reinsurance:
Current period	5,313	5,793	7,216	7,792
Prior period	8,006	5,279	16,819	12,523
Total net loss and LAE payments	13,319	11,072	24,035	20,315
Net reserves - end of period	56,365	35,942	56,365	35,942
Plus: reinsurance recoverables on unpaid losses	10,552	5,890	10,552	5,890
Gross reserves - end of period	$ 66,917	$ 41,832	$ 66,917	$ 41,832