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Investments - Related Parties - 4455 LBJ Freeway, LLC (Details) - 4455 LBJ Freeway, LLC - Related Parties - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Schedule of Equity Method Investments
Equity investment in unconsolidated subsidiaries	$ 1,563		$ 1,563		$ 1,074
4455 LBJ Freeway, LLC
Schedule of Equity Method Investments
Rent expense	623	$ 607	1,859	$ 1,813
VIE, Not primary beneficiary
Schedule of Equity Method Investments
Equity in earnings (losses)	$ 110	$ 63	$ 489	$ 191
VIE, Not primary beneficiary \| AmTrust Financial Services, Inc.
Schedule of Equity Method Investments
Ownership percentage	50.00%		50.00%