Cash and Cash Equivalents - Additional Information (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Cash And Cash Equivalents [Abstract]
Cash and cash equivalents	$ 165,910,000	$ 153,807,000	$ 36,073,000	$ 35,345,000
Cash in transit for credit and debit card transactions	3,500,000	2,000,000
Restricted cash	$ 580,000	$ 564,000
Restricted cash, asset, statement of financial position [extensible list]	us-gaap:OtherAssets