Description of business	12 Months Ended
Description of business	Dec. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of business	1. Description of business: The operations of Capital Properties, Inc. and its wholly-owned subsidiary, Tri-State Displays, Inc. (collectively “the Company”) consist of the long-term leasing of certain of its real estate interests in the Capital Center area in downtown Providence, Rhode Island (upon the commencement of which the tenants have been required to construct buildings thereon, with the exception of the parking garage and Parcel 20) and the leasing of locations along interstate and primary highways in Rhode Island and Massachusetts to Lamar Outdoor Advertising, LLC (“Lamar”) on which Lamar has constructed outdoor advertising boards. The Company anticipates that the future development of its remaining properties in the Capital Center area will consist primarily of long-term ground leases. Pending this development, the Company leases these undeveloped parcels (other than Parcel 6C) for public parking to Metropark, Ltd.

CAPITAL PROPERTIES INC /RI/ 10-K