Liability for Unpaid Losses and Loss Adjustment Expenses Liability for Unpaid Losses and Loss Adjustment Expenses (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016	Dec. 31, 2015
Liability for Unpaid Claims and Claims Adjustment Expense [Roll Forward]
Unpaid losses and loss adjustment expenses	$ 141,102	$ 88,446	$ 140,855	$ 76,792
Reinsurance Recoverable for Unpaid Claims and Claims Adjustments	20,152	911	18,724	2,114
Liability for Unpaid Claims and Claims Adjustment Expense, Net	120,950	87,535	$ 122,131	$ 74,678
Current Year Claims and Claims Adjustment Expense	63,859	61,072
Prior Year Claims and Claims Adjustment Expense	(526)	3,186
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred Claims	63,333	64,258
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Current Year	21,986	23,691
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid, Prior Years	42,528	27,710
Liability for Unpaid Claims and Claims Adjustment Expense, Claims Paid	64,514	51,401
Liability for Unpaid Claims and Claims Adjustment Expense, Reported Claims, Amount	82,987	53,006
Liability for Unpaid Claims and Claims Adjustment Expense, Incurred but Not Reported (IBNR) Claims, Amount	$ 58,115	$ 35,440