Debt (Summary Of Notes Payable) (Details) - USD ($)								2 Months Ended	3 Months Ended		12 Months Ended
		Mar. 05, 2019	Feb. 05, 2018	Dec. 29, 2016	Dec. 13, 2016	Aug. 31, 2016	Mar. 03, 2016	Apr. 30, 2018	Mar. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Debt Instrument [Line Items]
Contractual Facility									$ 290,879,000		$ 252,929,000
Balance Gross									183,768,000		167,043,000
Balance Net									180,009,000	[1]	162,740,000	[2]
Deferred financing costs, net									$ 3,800,000		$ 4,300,000
Trust Preferred Securities [Member]
Debt Instrument [Line Items]
Maturity date									Apr. 30, 2027		Apr. 30, 2027
Contractual Facility									$ 27,913,000		$ 27,913,000
Balance Gross									27,913,000.00		27,913,000
Balance Net									$ 26,116,000.00	[1]	$ 26,061,000	[2]
Stated Interest Rate									6.75%		6.52%
Effective interest rate									6.75%	[3]	6.52%	[4]
Bank Of America Credit Facility [Member]
Debt Instrument [Line Items]
Maturity date		May 01, 2020							May 01, 2020		May 01, 2020
Contractual Facility							$ 55,000,000		$ 55,000,000		$ 55,000,000
Balance Gross									30,000,000.00		25,000,000
Balance Net									$ 30,000,000.00	[1]	$ 25,000,000	[2]
Stated Interest Rate									5.02%		5.02%
Effective interest rate									5.02%	[3]	5.02%	[4]
US Bank Of America Line Of Credit [Member]
Debt Instrument [Line Items]
Maturity date									Oct. 31, 2019		Oct. 31, 2019
Contractual Facility									$ 5,000,000		$ 5,000,000
Balance Gross									3,500,000.00
Balance Net	[1]								$ 3,500,000.00
Stated Interest Rate									5.52%		5.48%
Effective interest rate									5.52%	[3]	5.48%	[4]
US Banc Of America Digital Projector Loan [Member]
Debt Instrument [Line Items]
Maturity date									Dec. 28, 2019		Dec. 28, 2019
Contractual Facility			$ 4,600,000					$ 4,900,000	$ 1,979,000		$ 2,604,000
Balance Gross									1,979,000.00		2,604,000
Balance Net									$ 1,979,000.00	[1]	$ 2,604,000	[2]
Stated Interest Rate									5.00%		5.00%
Effective interest rate									5.00%	[3]	5.00%	[4]
US Cinema 1, 2, 3 Term Loan [Member]
Debt Instrument [Line Items]
Maturity date									Sep. 01, 2019		Sep. 01, 2019
Contractual Facility						$ 15,000,000			$ 18,978,000		$ 19,086,000
Balance Gross									18,978,000.00		19,086,000
Balance Net									$ 18,768,000.00	[1]	$ 18,838,000	[2]
Stated Interest Rate									3.25%		3.25%
Effective interest rate									3.25%	[3]	3.25%	[4]
Minetta And Orpheum Theatres Loan [Member]
Debt Instrument [Line Items]
Maturity date									Nov. 01, 2023		Nov. 01, 2023
Contractual Facility									$ 8,000,000		$ 8,000,000		$ 7,500,000
Balance Gross									8,000,000.00		8,000,000
Balance Net									$ 7,864,000.00	[1]	$ 7,857,000	[2]
Stated Interest Rate									4.54%		4.88%
Effective interest rate									4.54%	[3]	4.88%	[4]
U.S. Corporate Office Term Loan [Member]
Debt Instrument [Line Items]
Maturity date									Jan. 01, 2027		Jan. 01, 2027
Contractual Facility					$ 8,400,000				$ 9,437,000		$ 9,495,000
Balance Gross									9,437,000.00		9,495,000
Balance Net									$ 9,319,000.00	[1]	$ 9,373,000	[2]
Effective interest rate									4.61%	[3]	4.61%	[4]
Union Square Construction Financing [Member]
Debt Instrument [Line Items]
Maturity date									Dec. 29, 2019		Dec. 29, 2019	[5]
Contractual Facility				$ 57,500,000					$ 57,500,000		$ 57,500,000	[5]
Balance Gross									33,934,000.00		27,182,000	[5]
Balance Net									$ 32,463,000.00	[1]	$ 25,280,000	[2],[5]
Effective interest rate									8.02%	[3]	8.35%	[4],[5]
NAB Corporate Loan Facility [Member]
Debt Instrument [Line Items]
Maturity date									Dec. 31, 2023	[6]	Dec. 31, 2023	[5]
Contractual Facility									$ 85,248,000	[6]	$ 46,856,000	[5]
Balance Gross									40,138,000.00	[6]	37,696,000	[5]
Balance Net									$ 40,111,000.00	[1],[6]	$ 37,660,000	[2],[5]
Stated Interest Rate									2.70%	[6]	3.05%	[5]
Effective interest rate									2.70%	[3],[6]	3.05%	[4],[5]
Westpac Bank Corporate Credit Facility [Member]
Debt Instrument [Line Items]
Maturity date									Dec. 31, 2023	[6]	Dec. 31, 2023	[5]
Contractual Facility									$ 21,824,000	[6]	$ 21,475,000	[5]
Balance Gross									9,889,000.00	[6]	10,067,000	[5]
Balance Net									$ 9,889,000.00	[1],[6]	$ 10,067,000	[2],[5]
Stated Interest Rate									3.80%	[6]	3.80%	[5]
Effective interest rate									3.80%	[3],[6]	3.80%	[4],[5]
Minimum [Member] | U.S. Corporate Office Term Loan [Member]
Debt Instrument [Line Items]
Stated Interest Rate									4.44%		4.44%
Minimum [Member] | Union Square Construction Financing [Member]
Debt Instrument [Line Items]
Stated Interest Rate									6.76%		6.76%
Maximum [Member] | U.S. Corporate Office Term Loan [Member]
Debt Instrument [Line Items]
Stated Interest Rate									4.64%		4.64%
Maximum [Member] | Union Square Construction Financing [Member]
Debt Instrument [Line Items]
Stated Interest Rate									12.51%		12.51%

[1] Net of deferred financing costs amounting to $3.8 million.

[2] Net of deferred financing costs amounting to $4.3 million.

[3] Both interest rate derivatives associated with the Trust Preferred Securities and Bank of America Credit Facility expired in October 2017 so the effective interest rate no longer applies as of March 31, 2019.

[4] Both interest rate derivatives associated with the Trust Preferred Securities and Bank of America Credit Facility expired in October 2017 so the effective interest rate no longer applies as of December 31, 2018.

[5] The contractual facilities and outstanding balances of the foreign currency denominated borrowings were translated into U.S. dollars based on the applicable exchange rates as of December 31, 2018.

[6] The contractual facilities and outstanding balances of the foreign currency denominated borrowings were translated into U.S. dollars based on the applicable exchange rates as of March 31, 2019.