Financing Activity - Interest Expense and Deferred Financing Amortization (Details) - Credit Agreements - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
2018 Revolving Facility
Debt Instrument [Line Items]
Interest expense	$ 1,827	$ 248	$ 3,061	$ 613
Deferred financing amortization	274	304	548	504
Term Loans
Debt Instrument [Line Items]
Interest expense	5,127	4,499	10,265	8,785
Deferred financing amortization	$ 190	190	$ 379	381
Accelerated financing costs		$ 363		$ 363