Reinsurance - Summary of Premiums Earned and Losses Incurred (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Reinsurance Disclosures [Abstract]
Premiums earned - Direct	$ 259,428	$ 255,387
Premiums earned - Assumed	98	208
Premiums earned - Ceded	(30,423)	(34,254)
Net premiums earned	229,103	221,341
Losses incurred - Direct	32,413	92,432
Losses incurred - Assumed	105	101
Losses incurred - Ceded	(4,899)	(7,521)
Net losses incurred	$ 27,619	$ 85,012