Long-Term Debt and Short-Term Borrowings (Details) - USD ($)	Sep. 30, 2021	Dec. 31, 2020
Long-Term Debt and Short-Term Borrowings
Mortgage notes	$ 24,478,000	$ 24,482,000
Senior notes	90,000,000	100,000,000
Unsecured term note due February 2025, with monthly principal and interest payments of $39,110, bearing interest at 5.75%	1,452,000	1,735,000
Convertible senior notes	100,050,000	100,050,000
Payroll Protection Program loans	3,426,000	3,424,000
Revolving credit agreement	33,000,000
Debt issuance costs	(4,083,000)	(3,684,000)
Total debt, net of debt issuance costs	248,323,000	226,007,000
Less current maturities, net of issuance costs	11,712,000	10,548,000
Less debt discount		22,423,000
Long-term debt	236,611,000	193,036,000
Short-term borrowings	49,796,000	87,194,000
Total debt and short-term borrowings, net of issuance costs	$ 298,119,000	$ 313,201,000