Investments in Real Estate and Real Estate Under Construction - Narrative (Details) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2016 USD ($) Property	Sep. 30, 2015 USD ($)	Dec. 31, 2015 USD ($) Property
Business Acquisition [Line Items]
Aggregate acquisition expenses	$ 329	$ 1,119
Construction in progress	137,576		$ 95,402
Proceeds from sale of real estate	293,634	156,475
Real estate, at cost	31,312		16,590
Other assets	119		0
Real estate, other liabilities	2,220		32
LCIF [Member]
Business Acquisition [Line Items]
Construction in progress	32,613		9,223
Proceeds from sale of real estate	185,219	0
Impairment of real estate	67,935
Certain Properties [Member] | LCIF [Member]
Business Acquisition [Line Items]
Proceeds from sale of real estate	445,565
Gain on sale of properties	16,029
Payments of debt extinguishment costs	$ 7,388
Number of real estate properties held for sale | Property	1
Real estate, at cost	$ 9,714
Deferred rent receivable	1,304
Deferred expense	610
Other assets	9
Real estate, other liabilities	2,206
Development Deals [Member]
Business Acquisition [Line Items]
Capitalized interest	5,180		$ 2,726
Equity Method Investments [Member] | Net Lease Strategic Assets Fund L.P. [Member] | LCIF [Member]
Business Acquisition [Line Items]
Contributions to equity method investment	$ 81	$ 1,623
New York, New York [Member]
Business Acquisition [Line Items]
Lease term (in years)	99 years
Deferred rent receivables, written off	$ 91,213
Number of real estate properties held for sale | Property	3		2
New York, New York [Member] | LCIF [Member]
Business Acquisition [Line Items]
Number of properties sold | Property	3
Lease term (in years)	99 years
Deferred rent receivables, written off	$ 91,213