General - Lease Assets and Liabilities and Maturity Dates of Leases (Details) $ in Thousands	Mar. 31, 2019 USD ($)
Components of lease assets and liabilities:
Operating lease right-of-use assets	$ 56,008
Current operating lease liabilities	$ 14,200
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued Liabilities, Current
Long-term operating lease liabilities	$ 50,015
Total operating lease liabilities	64,215
Finance lease assets	$ 15,611
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Property, Plant and Equipment, Net
Current finance lease liabilities	$ 4,192
Finance Lease, Liability, Current, Statement of Financial Position [Extensible List]	Long-term Debt and Capital Lease Obligations, Current
Long-term finance lease liabilities	$ 16,936
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Long-term Debt and Capital Lease Obligations
Total finance lease liabilities	$ 21,128
Maturity dates of leases:
2019	14,648
2020	16,885
2021	16,248
2022	15,217
2023	11,228
2024 and beyond	13,672
Total lease payments	87,898
Less interest	(2,555)
Present value of lease liabilities	$ 85,343
Weighted average remaining lease term
Operating leases	4 years 9 months 22 days
Finance leases	5 years 3 months 29 days
Weighted average discount rate
Operating leases	4.79%
Finance leases	4.53%