Accounts Payable, Accrued Expenses and Other Liabilities (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019
Accounts Payable [Line Items]
Contingent Consideration Payable		$ 37,953	$ 30,896
Interest and Dividends Payable		17,031	5,828
Loss reserves and claims incurred but not reported	[1]	37,036	30,282
Professional Fees Payable		9,495	4,789
Unearned Premiums	[1]	14,732	16,092
Fees Payable		4,459	4,628
Accrued Income Taxes		17,204
Accrued tax liabilities		14,100	2,778
SEC fees payable		9,987	3,957
Software contracts payable		1,852	2,884
Performance fees payable		4,427	3,708
Accrued expenses and accounts payable	[2]	42,303	35,714
Accounts payable, accrued expenses and other liabilities		196,479	141,556
Hollenfels
Accounts Payable [Line Items]
Reinsurance Premiums Payable		$ 15,500	$ 13,200

[1] Balances relate to the Company's reinsurance business (See Note 18).

[2] As of December 31, 2020 and 2019, the balance includes reinsurance premiums payable of $15.5 million and $13.2 million, respectively.