Reflects the revenue, comprised of base and incentive revenue derived from the management of joint ventures, managing third-party properties, or another entity's operations. Additionally, reflects the sum of all other revenue and income recognized by the entity in the period not otherwise specified in the income statement.

No definition available.

Related Parties - Additional Information (Details)	3 Months Ended		9 Months Ended
Related Parties - Additional Information (Details)	Sep. 30, 2019 USD ($) ft²	Sep. 30, 2018 USD ($)	Sep. 30, 2019 USD ($) ft²	Sep. 30, 2018 USD ($)	Aug. 21, 2019 USD ($) ft²	Dec. 31, 2018 USD ($)
Related Party Transaction [Line Items]
Fee and other income	$ 10,238,000	$ 7,522,000	$ 26,857,000	$ 22,811,000
Accounts and other receivables, net	20,400,000		20,400,000			$ 20,076,000
Property management, asset management, leasing and other related services fee income	7,159,000	4,079,000	17,371,000	12,953,000
Transaction related costs	786,000	450,000	1,704,000	863,000
Accounts payable and accrued expenses	$ 119,362,000		$ 119,362,000			124,334,000
Area of office and retail properties \| ft²	12,400,000		12,400,000
712 Fifth Avenue [Member]
Related Party Transaction [Line Items]
Equity method paramount ownership percentage	50.00%		50.00%
55 Second Street [Member]
Related Party Transaction [Line Items]
Equity method paramount ownership percentage	44.10%		44.10%
Area of office and retail properties \| ft²					384,000
Transaction valued property value					$ 401,700,000
CNBB-RDF Holdings Otto Family [Member] \| 55 Second Street [Member]
Related Party Transaction [Line Items]
Transaction valued property value					$ 5,000,000
CNBB-RDF Holdings Otto Family [Member] \| Imperial Associates, LP [Member] \| 55 Second Street [Member]
Related Party Transaction [Line Items]
Equity method ownership percentage by related party					2.30%
CNBB-RDF Holdings Otto Family [Member] \| Management Agreements [Member]
Related Party Transaction [Line Items]
Fee and other income	$ 212,000	632,000	$ 200,000	624,000
Accounts and other receivables, net	0		0			51,000
Unconsolidated Joint Ventures and Real Estate Funds [Member] \| Management Agreements [Member]
Related Party Transaction [Line Items]
Accounts and other receivables, net	2,573,000		2,573,000			1,836,000
Property management, asset management, leasing and other related services fee income	$ 4,880,000	3,235,000	$ 12,938,000	10,329,000
Hamburg Trust Consulting GMBH ("HTC") [Member]
Related Party Transaction [Line Items]
Mark-up cost percentage	10.00%		10.00%
Transaction related costs	$ 72,000	69,000	$ 758,000	129,000
Accounts payable and accrued expenses	$ 72,000		$ 72,000			$ 40,000
Hamburg Trust Consulting GMBH ("HTC") [Member] \| Chairman, Chief Executive Officer and President [Member]
Related Party Transaction [Line Items]
Percentage of ownership	100.00%		100.00%
Mannheim Trust [Member] \| Board of Director [Member] \| 712 Fifth Avenue [Member]
Related Party Transaction [Line Items]
Equity method paramount ownership percentage	50.00%		50.00%
Lease rental income	$ 90,000	$ 92,000	$ 271,000	$ 273,000
Kramer Design Services [Member] \| 712 Fifth Avenue [Member]
Related Party Transaction [Line Items]
Equity method paramount ownership percentage	50.00%		50.00%
Expense recognized	$ 183,000		$ 286,000
Joint Venture [Member] \| 55 Second Street [Member]
Related Party Transaction [Line Items]
Equity method paramount ownership percentage					44.10%
Area of office and retail properties \| ft²					384,000
Transaction valued property value					$ 401,700,000
Mortgage debt					$ 187,500,000