Reinsurance - Effects of Reinsurance and Assumption Transactions (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Written premiums:
Direct									$ 89,915	$ 90,503	$ 78,296
Assumed									25,008	3,247	5,551
Ceded									(14,994)	(14,076)	(17,548)
Net written premiums	$ 27,069	$ 24,634	$ 26,176	$ 22,050	$ 21,467	$ 28,599	$ 15,942	$ 13,666	99,929	79,674	66,299
Earned premiums:
Direct									90,660	82,614	66,608
Assumed									14,053	6,602	361
Ceded									(15,086)	(22,451)	(9,441)
Net earned premiums	24,463	23,380	21,675	20,109	19,274	17,883	15,115	14,493	89,627	66,765	57,528
Loss and loss adjustment expenses:
Direct									59,940	43,989	43,894
Assumed									11,955	2,756	107
Ceded									(12,892)	(7,863)	(3,271)
Net Loss and loss adjustment expenses	$ 18,181	$ 14,582	$ 13,541	$ 12,699	$ 11,523	$ 9,813	$ 8,976	$ 8,570	$ 59,003	$ 38,882	$ 40,730