Summary of Significant Accounting Policies (Details)	3 Months Ended	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2017 USD ($) segment properties	Dec. 31, 2016 USD ($) properties	Dec. 31, 2015 USD ($)	Apr. 06, 2017 USD ($)
mortgage note receivable balance from rental property conversion		$ 12,100,000
Minimum term of existing long-term triple-net lease or lease for business acquisition		7 years
Deferred financing costs, net		$ 32,852,000	$ 29,320,000
Number of Reportable Operating Segments | segment		4
Accounting for Acquisitions [Abstract]
Transaction costs		$ 523,000	7,869,000	$ 7,518,000
Goodwill		693,000	693,000
Intangible Assets, Net (Including Goodwill)		28,869,000	14,888,000
Amortization of above/below market leases and tenant allowances, net		(107,000)	183,000	192,000
Below Market Lease, Net		(8,792,000)	(109,000)		$ (7,611,000)
Revenue Recognition [Abstract]
Straight Line Rent		4,300,000	17,000,000	12,200,000
Percentage rents		7,800,000	4,700,000	3,000,000
Participating interest income		700,000	800,000	1,500,000
prepayment fee		$ 800,000	3,600,000	0
Income Tax Disclosure [Abstract]
Percent of taxable income distributed to shareholders annually		90.00%
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent		35.00%
Current Federal Tax Expense (Benefit)		$ 0
Deferred TRS Income Tax Expense (Benefit)		$ (137,000)	$ (273,000)	$ 0
Effective Income Tax Rate Reconciliation, Percent		0.90%	0.20%	0.20%
Other		$ 12,118,000	$ 12,258,000
Deferred Tax Liabilities, Undistributed Foreign Earnings		125,000
Payments Related to Tax Withholding for Repatriation of Foreign Earnings		$ 44,000
Enacted Corporate tax rate, percent		21.00%
Deferred Tax Assets, Gross		$ 16,015,000	16,981,000
Deferred Tax Liabilities, Gross		3,897,000	4,723,000
Deferred Tax Liabilities		410,000
Current Income and Withholding Tax Expense		(1,600,000)	1,700,000	$ 1,600,000
Provision for income tax expense		0	0	0
Income Tax Examination, Penalties and Interest Expense				65,000
Concentration Risks, Types, No Concentration Percentage [Abstract]
Rental revenue		468,648,000	399,589,000	330,886,000
Share-based Compensation [Abstract]
Share based compensation		$ 14,142,000	11,164,000	8,508,000
Share based compensation, future vesting period minimum (in years)		4 years
Share-based compensation expense included in retirement severance expense		$ 0	0	6,377,000
Retirement severance expense		$ 0	$ 0	$ 18,578,000
Impaired notes receivable	0	0	0	0
Loans and Leases Receivable, Allowance	$ 3,800,000			$ 3,800,000
American Multi-Cinema, Inc. [Member]
Concentration Risks, Types, No Concentration Percentage [Abstract]
Percent of megaplex theatre rental leased by AMC		34.00%
Rental revenue		$ 114,400,000	$ 90,000,000	$ 86,100,000
Percentage of lease revenue in total revenue		19.90%	18.20%	20.00%
Carmike Cinemas, Inc [Member]
Concentration Risks, Types, No Concentration Percentage [Abstract]
Rental revenue			$ 21,700,000
Percentage of lease revenue in total revenue			4.40%
Leases, Acquired-in-Place [Member]
Accounting for Acquisitions [Abstract]
Intangible assets, accumulated amortization		$ 5,500,000	$ 13,400,000
Number of properties acquired | properties		35	24
Weighted average useful life for in-place leases		12 years 6 months
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2018		$ 2,420,000
2019		2,181,000
2020		1,907,000
2021		1,796,000
2022		1,695,000
Thereafter		11,513,000
Total		21,512,000	$ 13,716,000
Lease Agreements [Member]
Accounting for Acquisitions [Abstract]
Amortization		2,000,000	1,400,000	$ 1,400,000
Above Market Leases [Member]
Accounting for Acquisitions [Abstract]
Intangible assets, accumulated amortization		$ 800,000	$ 600,000
Number of properties acquired | properties		2	2,000
Amortization of above/below market leases and tenant allowances, net		$ 194,000	$ 192,000	192,000
Weighted average useful life for in-place leases		3 years 2 months
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2018		$ 197,000
2019		102,000
2020		6,000
2021		6,000
2022		6,000
Thereafter		34,000
Total		$ 351,000	479,000
Trade Names [Member]
Accounting for Acquisitions [Abstract]
Number of properties acquired | properties		12
Non-amortizing indefinite lived trade names		$ 5,400,000
Amortization		$ 0
Weighted average useful life for in-place leases		33 years 2 months
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2018		$ 30,000
2019		30,000
2020		30,000
2021		30,000
2022		30,000
Thereafter		806,000
Total		956,000	0
Indefinite and Finite-lived Intangible Assets, net		6,313,000
Below market leases [Member]
Accounting for Acquisitions [Abstract]
Intangible assets, accumulated amortization		$ 300,000	0
Number of properties acquired | properties		7
Amortization of above/below market leases and tenant allowances, net		$ 307,000	12,000
Weighted average useful life for in-place leases		30 years 10 months
Finite-Lived Intangible Assets, Future Amortization Expense [Abstract]
2018		$ 458,000
2019		458,000
2020		446,000
2021		426,000
2022		410,000
Thereafter		6,594,000
Total		8,792,000
CANADA
Income Tax Disclosure [Abstract]
Other		$ 11,700,000
Minimum [Member]
Share-based Compensation [Abstract]
Share based compensation, future vesting period minimum (in years)		3 years
Minimum [Member] | Building [Member]
Rental Properties [Abstract]
Estimated useful live of buildings (in years)		30 years
Minimum [Member] | Furniture and Fixtures [Member]
Rental Properties [Abstract]
Estimated useful live of buildings (in years)		3 years
Minimum [Member] | Building Improvements [Member]
Rental Properties [Abstract]
Estimated useful live of buildings (in years)		10 years
Maximum [Member]
Share-based Compensation [Abstract]
Share based compensation, future vesting period minimum (in years)		4 years
Maximum [Member] | Building [Member]
Rental Properties [Abstract]
Estimated useful live of buildings (in years)		40 years
Maximum [Member] | Furniture and Fixtures [Member]
Rental Properties [Abstract]
Estimated useful live of buildings (in years)		25 years
Maximum [Member] | Building Improvements [Member]
Rental Properties [Abstract]
Estimated useful live of buildings (in years)		20 years
Stock Options [Member]
Share-based Compensation [Abstract]
Share based compensation, future vesting period minimum (in years)		4 years
Stock or Unit Option Plan Expense		$ 700,000	900,000	1,100,000
Restricted Stock [Member] | Employee [Member]
Share-based Compensation [Abstract]
Share based compensation expense related to employees and trustees		$ 12,200,000	9,200,000	6,300,000
Restricted Stock [Member] | Minimum [Member] | Employee [Member]
Share-based Compensation [Abstract]
Share based compensation, future vesting period minimum (in years)		3 years
Restricted Stock [Member] | Maximum [Member] | Employee [Member]
Share-based Compensation [Abstract]
Share based compensation, future vesting period minimum (in years)		4 years
Restricted Stock Units (RSUs) [Member] | Non-Employee Trustees [Member]
Share-based Compensation [Abstract]
Share based compensation expense related to employees and trustees		$ 1,300,000	1,100,000	1,000,000
Allowance for Doubtful Accounts [Member]
Allowance for Doubtful Accounts [Abstract]
Allowance for doubtful accounts	3,210,000	$ 7,485,000	$ 871,000	3,210,000
Employee Severance [Member] | Accelerated Vesting of Shares [Member] | Chief Executive Officer [Member] | Stock Options [Member]
Share-based Compensation [Abstract]
Retirement severance expense	$ 1,400,000			1,400,000
Employee Severance [Member] | Accelerated Vesting of Shares [Member] | Chief Executive Officer [Member] | Nonvested Shares [Member]
Share-based Compensation [Abstract]
Retirement severance expense				$ 5,000,000
Theatre Project China Member | CHINA
Income Tax Disclosure [Abstract]
Number of Real Estate Properties | properties		4