Leases - Narrative (Details) ft² in Thousands, $ in Thousands	Sep. 30, 2019 USD ($) ft²	Jan. 01, 2019 USD ($)	Dec. 31, 2018 USD ($)
Leases [Line Items]
Operating lease, right-of-use asset	$ 370,604		$ 0
Operating lease liabilities	490,978		0
Reclassification from other liabilities	(266,090)		(311,806)
Reclassification from deferred revenue	(62,583)		(167,730)
Reclassification from identified intangible assets, net	(30,773)		(136,781)
Reclassification from other assets	$ (446,516)		$ (431,938)
Accounting Standards Update 2016-02
Leases [Line Items]
Operating lease, right-of-use asset		$ 526,866
Operating lease liabilities		526,866
Reclassification from other liabilities		37,269
Reclassification from deferred revenue		4,267
Reclassification from identified intangible assets, net		23,665
Reclassification from other assets		$ 1,584
Farley Office and Retail Building
Leases [Line Items]
Equity method ownership percentage	95.00%
Square footage of real estate property (in sqft) | ft²	845
Lessee, operating lease, lease not yet commenced, term (years)	99 years
Farley Office and Retail Building | Office Space
Leases [Line Items]
Square footage of real estate property (in sqft) | ft²	725
Farley Office and Retail Building | Retail
Leases [Line Items]
Square footage of real estate property (in sqft) | ft²	120