Net Investment in Leases (Narrative) (Details) $ in Thousands	1 Months Ended	12 Months Ended
	May 31, 2019 USD ($) property	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Repurchase Agreement Counterparty [Line Items]
Payments to acquire real estate assets	$ 56,700	$ 240,487	$ 19,454	$ 6,600
Number of properties acquired from lessee | property	7
Purchase price for properties acquired from lessee	$ 44,100	44,300
Extension of existing master net leases (in years)	15 years
Net investment in leases	$ 424,100	418,915	$ 0
Real estate assets derecognized at inception of sales-type lease	193,400
Deferred operating lease income receivable derecognized at inception of sales-type lease	25,400
Deferred expenses and other assets derecognized at inception of sales-type lease	13,400
Accounts payable, accrued expenses, and other liabilities derecognized at inception of sales-type lease	$ 1,900
Selling profit from sales-type leases		180,416
Interest income from sales-type leases		20,500
Impairment of real estate		900
Bowling Entertainment Venue Operator
Repurchase Agreement Counterparty [Line Items]
Number of properties acquired from lessee | property	9
Bowling Center Commitment | Bowling Entertainment Venue Operator
Repurchase Agreement Counterparty [Line Items]
Commitment to invest additional bowling centers	$ 55,000	$ 55,000
Loans Receivable And Other Lending Investments, Net
Repurchase Agreement Counterparty [Line Items]
Purchase price for properties acquired from lessee	$ 44,100