Derivative Financial Instruments - Changes in Fair Value of Derivative Contracts (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax:
Net loss (gain) recognized in other comprehensive loss	$ 1,062	$ (573)	$ 4,554	$ 8,167
Gain recognized in earnings	200	(1,500)	1,600	(2,200)
Interest rate swap agreements
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax:
Gain recognized in earnings	(35)	(36)	(105)	(110)
Derivative contracts
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax:
Beginning balance	12,651	17,881	15,989	9,238
Loss (gain) recognized in other comprehensive loss	(264)	(72)	(2,548)	9,212
Amounts reclassified from other comprehensive loss to earnings	(499)	(501)	(1,483)	(1,068)
Net loss (gain) recognized in other comprehensive loss	(763)	(573)	(4,031)	8,144
Ending balance	$ 11,853	$ 17,272	$ 11,853	$ 17,272