Lease Information - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) a lease	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)
Operating Leased Assets [Line Items]
Operating lease, term of contract (in years)	4 years 6 months 6 days
Operating leases, earned overage rent revenue	$ 1.2	$ 1.1	$ 1.5
Number of properties subject to lease | lease	9
Area of land (in acres) | a	47
Rent expense	$ 1.7	$ 1.7	$ 1.8
Minimum
Operating Leased Assets [Line Items]
Extension option (in years)	5 years
Length of extension option (in years)	20 years
Maximum
Operating Leased Assets [Line Items]
Extension option (in years)	10 years
Length of extension option (in years)	25 years