Borrowing Facilities - Long-term debt outstanding (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019
Line of Credit Facility [Line Items]
Less unamortized debt issuance costs	$ (1,387)	$ (1,616)
Long-term debt	169,238	142,759
Revolving credit facility, due 2023 [Member]
Line of Credit Facility [Line Items]
Principal amount	30,000	0
Term loan, due 2023 [Member]
Line of Credit Facility [Line Items]
Principal amount	$ 140,625	$ 144,375