Line of Credit (Details) - USD ($)	Mar. 31, 2020	Dec. 31, 2019
Line of Credit Facility [Line Items]
Line of credit	$ 99,540,000	$ 107,140,000
Credit And Security Agreement, 2018
Line of Credit Facility [Line Items]
Letters of credit outstanding, amount	200,000
Credit And Security Agreement, 2018 | Line of Credit
Line of Credit Facility [Line Items]
Letters of credit issued	$ 25,260,000