Derivative Instruments and Hedging Activities (Details)	3 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2021 USD ($) Instrument	Jun. 30, 2021 USD ($)	Dec. 31, 2020
Derivatives, Fair Value [Line Items]
Basis spread on variable rate		1.50%
Debt instrument, interest rate, increase (decrease)		0.50%
Long-term debt, percentage bearing fixed interest, amount		$ 210,000,000
Long-term debt, percentage bearing variable interest, amount		$ 0
Maximum [Member]
Derivatives, Fair Value [Line Items]
Basis spread on variable rate		2.875%
Interest Rate Swap No. 1 [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount		$ 25,000,000
Derivative, fixed interest rate		2.50%
Derivative, maturity date		Aug. 29, 2024
Derivative, term of contract		5 years	5 years
Interest Rate Swap No. 2 [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount		$ 25,000,000
Derivative, fixed interest rate		1.30%
Derivative, maturity date		Feb. 28, 2025
Derivative, term of contract		10 years	10 years
New Blended and Extended Interest Swap Agreement [Member]
Derivatives, Fair Value [Line Items]
Derivative, notional amount		$ 60,000,000
Forward Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Derivative, number of instruments held | Instrument	2
Derivative, notional amount	$ 35,000,000	$ 60,000,000
Gain on forward interest rate swap agreements terminated and settlements	$ 1,400,000
Derivative, term of contract		10 years	10 years
Number of interest rate swap agreements were terminated and settled during the period. | Instrument	2