Debt (Details Textual) - USD ($) $ in Thousands	1 Months Ended	3 Months Ended
	May 31, 2017	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Loss on debt extinguishments		$ 0
Book value		321,443	$ 272,751
Senior Notes due 2024
Debt Instrument [Line Items]
Net unamortized debt issuance costs		2,800	3,100
Debt Instrument, Face Amount	$ 250,000
Proceeds from Debt	$ 245,000
Revolving Credit Facility
Debt Instrument [Line Items]
Net unamortized debt issuance costs		$ 1,900	$ 2,300
Stated interest rate		2.70%
Book value		$ 60,000
Line of Credit Facility, Remaining Borrowing Capacity		169,500
Line of Credit Facility, Maximum Borrowing Capacity		250,000
Letters of Credit Outstanding, Amount		$ 20,500