Accumulated Other Comprehensive Loss - Reclassification out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Reclassifications out of accumulated other comprehensive income (loss):
Income tax benefit	$ (22,049)	$ (24,657)
Total reclassifications	35,816
Reclassification out of Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income (loss):
Total reclassifications	103	143
Reclassification out of Accumulated Other Comprehensive Income | Amortization of loss on interest rate hedge
Reclassifications out of accumulated other comprehensive income (loss):
Operating expenses	(120)
Income tax benefit	30
Total reclassifications	(90)
Reclassification out of Accumulated Other Comprehensive Income | Amortization of deferred actuarial loss and prior service cost
Reclassifications out of accumulated other comprehensive income (loss):
Operating expenses	257	192
Income tax benefit	(64)	(49)
Total reclassifications	$ 193	$ 143