Right-of-Use Assets and Lease Liabilities (Details)	3 Months Ended	6 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2019 USD ($)
Assets
Operating lease right-of-use-assets	$ 13,558,000	$ 13,558,000
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible List]	Operating lease right-of-use-assets	Operating lease right-of-use-assets
Liabilities
Operating lease liabilities (short-term)	$ 1,854,000	$ 1,854,000
Operating Lease, Liability, Current, Statement of Financial Position [Extensible List]	Accrued Liabilities, Current	Accrued Liabilities, Current
Operating lease liabilities (long-term)	$ 12,577,000	$ 12,577,000
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible List]	Operating lease liabilities (long-term)	Operating lease liabilities (long-term)
Total lease liabilities	$ 14,431,000	$ 14,431,000
Lease Costs
Lease costs	651,000	1,249,000
Variable lease costs	$ 0	$ 0
Minimum
Operating Lease
Renewal option term	1 year	1 year
Maximum
Operating Lease
Renewal option term	5 years	5 years