Commitments and Contingent Liabilities - Narrative (Details) $ in Thousands			9 Months Ended	12 Months Ended
	May 10, 2019 USD ($)	Jan. 01, 2019 USD ($)	Sep. 30, 2020 USD ($) option	Dec. 31, 2019 USD ($)
Loss Contingencies
Accounting Standards Update		us-gaap:AccountingStandardsUpdate201602Member		us-gaap:AccountingStandardsUpdate201613Member
Investments in leases - operating		$ 11,100
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]			us-gaap:OtherAssets	us-gaap:OtherAssets
Operating Lease, Liability, Statement of Financial Position [Extensible List]			us-gaap:OtherLiabilities	us-gaap:OtherLiabilities
Lease liability		$ 11,100	$ 17,671	$ 17,738
Finance lease, weighted average remaining lease term			38 years
Minimum
Loss Contingencies
Lessee, finance lease, discount rate (percent)			6.00%
Maximum
Loss Contingencies
Operating lease, discount rate (percent)	5.50%
Lessee, finance lease, discount rate (percent)			8.00%
Cascata Golf Course And Various Office In New Orleans And New York
Loss Contingencies
Weighted average remaining lease term			15 years 7 months 6 days
Cascata Golf Course
Loss Contingencies
Number of extension options | option			3
Renewal term			10 years
New York Offices
Loss Contingencies
Renewal term	5 years
Lessee, initial term	10 years
Expenses related to operating lease commitments	$ 900
New York Offices | Minimum
Loss Contingencies
Operating lease, discount rate (percent)	5.30%