Derivative Instruments and Hedging Activities - Schedule of Estimated Gross Fair Values of Derivative Instruments and Their Classification on Consolidated Balance Sheet (Details) - Interest Rate Swap Agreements - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Derivatives Designated as Effective Hedging Instruments | Cash Flow Hedges
Liabilities:
Derivative liabilities	$ 16,919	$ 20,377
Derivatives Not Designated as Hedging Instruments
Liabilities:
Derivative liabilities	13,497	16,260
Current Portion of Long-term Liabilities | Derivatives Designated as Effective Hedging Instruments | Cash Flow Hedges
Liabilities:
Current portion of long-term liabilities	7,895	8,205
Current Portion of Long-term Liabilities | Derivatives Not Designated as Hedging Instruments
Liabilities:
Current portion of long-term liabilities	6,300	6,548
Other Long-term Liabilities | Derivatives Designated as Effective Hedging Instruments | Cash Flow Hedges
Liabilities:
Other long-term liabilities	9,024	12,172
Other Long-term Liabilities | Derivatives Not Designated as Hedging Instruments
Liabilities:
Other long-term liabilities	$ 7,197	$ 9,712