Summary of Significant Accounting Policies - Narrative (Details)	3 Months Ended
	Mar. 31, 2018 USD ($) ft² item $ / shares shares	Mar. 31, 2017 USD ($)
Stock Issued During Period, Shares, New Issues | shares	3,126,998
Shares Issued, Price Per Share | $ / shares	$ 11.36
Marketing and Advertising Expense	$ 2,562,000	$ 3,860,000
Net cash used in investing activities	$ (19,117,000)	$ (29,000)
Square of feet of space | ft²	50,678
Lease term	10 years
Number of renewal periods | item	2
Term of lease extension option	5 years
Initial annual base rent	$ 1,214,000
Annual increase in base rent (per square foot)	$ 23.95
Minimum
Increase in annual base rent	2.50%
Maximum
Increase in annual base rent	3.10%