Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - 388-390 Greenwich Street $ in Millions	9 Months Ended
Sep. 30, 2016 USD ($)
Amortization of below market lease	$ 172.4
SL Green Operating Partnership
Amortization of below market lease	$ 172.4

Amount of amortization of acquired leases acquired as part of a real property acquisition at below market lease rate with a finite life.

No definition available.

Name:	us-gaap_AmortizationOfBelowMarketLease
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration