Leases - Balance Sheet Classification of Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Assets
Operating lease right-of-use assets	$ 19,354	$ 23,165	$ 0
Finance lease assets	483
Total leased assets	19,837
Current:
Operating	6,892		0
Finance	308
Long-term:
Operating	13,810		$ 0
Finance	199
Total lease liabilities	21,209
Finance lease, accumulated amortization	$ 208