Debt (Narratives) (Details) - USD ($)	3 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	May 04, 2021	Mar. 31, 2021
Debt Disclosure [Abstract]
Long-term Debt	$ 750,000,000			$ 545,000,000
Line of Credit Facility [Line Items]
Maximum availability under New Revolving Credit Facility	100,000,000
Line of Credit Facility, Maximum Borrowing Capacity	100,000,000
Outstanding borrowings	450,000,000
Current portion of long term debt and finance lease obligations	60,501,000			4,450,000
Deferred Costs	14,690,000
Accumulated Amortization, Deferred Finance Costs	269,000			8,744,000
Unsecured credit lines	2,608,000
Amount drawn on unsecured credit lines	$ 0
Stock Issued During Period, Shares, New Issues	4,312,500
Common Stock, Par or Stated Value Per Share			$ 48.00
Proceeds from Issuance or Sale of Equity	$ 207,000,000	$ 0
Lessee, Finance Lease, Term of Contract	23 years
Operating Income (Loss)	$ 10,746,000	1,789,000
Secured Debt	450,000,000			445,000,000
Long-term Debt	750,000,000			545,000,000
Extinguishment of Debt, Amount	14,803,000	$ 0
Short-term Debt	60,000,000
Dorner
Line of Credit Facility [Line Items]
Operating Income (Loss)	1,164,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Debt Issuance Costs, Gross	977,000
Revolving Credit Facility [Member] | Dorner
Line of Credit Facility [Line Items]
Debt Issuance Costs, Gross	3,050,000
Revolving Credit Facility [Member]
Line of Credit Facility [Line Items]
Accumulated Amortization, Deferred Finance Costs	201,000			2,313,000
Extinguishment of Debt, Amount	326,000
Debt Issuance Costs, Gross	4,027,000			$ 3,615,000
Required payments [Member]
Line of Credit Facility [Line Items]
Current portion of long term debt and finance lease obligations	4,500,000
Secured Debt
Line of Credit Facility [Line Items]
Extinguishment of Debt, Amount	5,946,000
Debt Issuance Costs, Gross	5,432,000
Bridge Loan
Line of Credit Facility [Line Items]
Extinguishment of Debt, Amount	8,531,000
New Revolving Credit Facility
Line of Credit Facility [Line Items]
Outstanding letters of credit	18,784,000
New Revolving Credit Facility | Standby Letters of Credit
Line of Credit Facility [Line Items]
Outstanding letters of credit	16,935,000
New Revolving Credit Facility | Letter of Credit
Line of Credit Facility [Line Items]
Outstanding letters of credit	1,849,000
New Revolving Credit Facility | Unsecured Lines of Credit
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	14,996,000
Outstanding borrowings	$ 11,837,000