Leases - Undiscounted Cash Flow of Lease Liabilities (Details)	Jun. 30, 2019 USD ($)
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
2019 (remaining six months)	$ 8,879,000
2020	18,400,000
2021	17,307,000
2022	14,746,000
2023	12,836,000
2024	11,402,000
2025 and thereafter	37,788,000
Total lease payments	121,358,000
Less: Imputed interest	(28,004,000)
Total operating lease liabilities	93,354,000
Less: Current lease obligations	(17,434,000)
Long-term lease obligations	$ 75,920,000