Summary of Significant Accounting Policies - Narrative (Details)	12 Months Ended
	Dec. 31, 2018 USD ($) segment	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Jan. 01, 2019 USD ($)
Accounting Policies [Line Items]
Deferred revenue	$ 4,100,000	$ 4,100,000
Advertising and marketing expense	8,900,000	7,600,000	$ 9,400,000
Interest costs capitalized	$ 1,600,000	$ 500,000	$ 0
Number of reportable segments (segment) | segment	2
Remaining contractual payments under ground lease agreements	$ 75,888,000
Capitalized internal leasing costs	$ 4,600,000
Building and Building Improvements
Accounting Policies [Line Items]
Useful life	39 years
Corporate Equipment | Minimum
Accounting Policies [Line Items]
Useful life	3 years
Corporate Equipment | Maximum
Accounting Policies [Line Items]
Useful life	7 years
Subsequent Event | ASU 2016-02
Accounting Policies [Line Items]
Operating lease, right-of-use assets				$ 30,000,000
Operating lease, liabilities				$ 30,000,000