Commitments and Contingencies - Fundings That May be Required (Details) - USD ($) $ in Thousands	1 Months Ended	9 Months Ended
	May 31, 2019	Sep. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Percentage of capital committed that may be drawn down		100.00%
Other Commitments [Line Items]
Performance-Based Commitments		$ 371,310
Strategic Investments		24,177
Total		395,487
Loans and Other Lending Investments
Other Commitments [Line Items]
Performance-Based Commitments		294,059
Strategic Investments		0
Total		294,059
Real Estate
Other Commitments [Line Items]
Performance-Based Commitments		77,251
Strategic Investments		0
Total		77,251
Other Investments
Other Commitments [Line Items]
Performance-Based Commitments		0
Strategic Investments		24,177
Total		24,177
Loan Participations
Other Commitments [Line Items]
Performance-Based Commitments		$ 16,800
Bowling Entertainment Venue Operator | Bowling center commitment
Other Commitments [Line Items]
Commitment to invest additional bowling centers	$ 55,000