Multiemployer Pension Plans - Narrative (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2020 USD ($) plan	Dec. 31, 2019 USD ($)
Multiemployer Plans [Line Items]
Multiemployer plans surcharge percentage	53.00%
Multiemployer plan, contributions	$ 16,109	$ 17,052
CBAs
Multiemployer Plans [Line Items]
Multiemployer plan, contributions	$ 16,100	$ 17,100
MEPP
Multiemployer Plans [Line Items]
Multiemployer plans number of employer | plan	40
MEPP | PPA
Multiemployer Plans [Line Items]
Multiemployer plans surcharge percentage	5.00%
MEPP | CBA
Multiemployer Plans [Line Items]
Multiemployer plans surcharge percentage	10.00%