Reinsurance - Effects of Reinsurance (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Reinsurance Recoverables
Reinsurance recoverable on paid losses	$ 300,954		$ 282,500
Reinsurance recoverable on unpaid losses	1,101,244		1,111,808
Reinsurance recoverable, allowance for expected credit losses	517		0
Reinsurance recoverable, net	1,401,681		1,394,308
Reinsurance Liabilities
Unpaid Loss and LAE reserves, assumed	46,868		50,884
Unearned premiums, assumed	17,193		15,278
Prepaid reinsurance premiums	511,648		$ 575,747
Premiums:
Direct, Written	1,458,533	$ 1,489,188
Assumed, Written	18,021	20,590
Gross premium written	1,476,554	1,509,778
Ceded premiums	(266,951)	(345,114)
Net premium written	1,209,603	1,164,664
Direct, Earned	1,390,150	1,315,705
Assumed, Earned	16,106	21,000
Premiums Earned, Gross	1,406,256	1,336,705
Ceded, Earned	(331,050)	(372,548)
Net earned premium	1,075,206	964,157
Loss and LAE expense:
Assumed Loss and LAE	6,635	5,322
Ceded Loss and LAE	$ 196,486	$ 209,322