Business Overview and Summary of Significant Accounting Policies - Components of Operating and Finance Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Operating lease cost:
Total operating lease costs	$ 665	$ 1,308
Finance lease cost:
Amortization of right-to-use assets	178	301
Interest on lease liabilities	40	62
Total financing lease cost	$ 218	$ 363