Acquisitions - Results of Operations Of Acquiree (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Morse TEC
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net investment income	$ 488
General and administrative expenses	(1,459)
Other expenses	(1,512)
Earnings of acquiree since acquisition date	$ (2,483)
Maiden Re
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net investment income		$ 675
General and administrative expenses		(435)
Net unrealized gains		3,749
Earnings of acquiree since acquisition date		3,989
KaylaRe
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Net investment income		3,096
General and administrative expenses		(2,164)
Net unrealized gains		(47,769)
Earnings of acquiree since acquisition date		(45,915)
Premiums earned		13,627
Incurred losses and LAE		(12,364)
Acquisition costs		(341)
Underwriting income		$ 922