Retirement Plans - Multiemployer Pension (Details)		12 Months Ended
	Jul. 01, 2017 USD ($)	Dec. 31, 2019 USD ($) employee	Dec. 31, 2018 USD ($)
Multiemployer pension
Number of unionized employees covered under CBA expiring on June 27, 2019 | employee		3
Multiemployer Plans, Pension | WAPA
Multiemployer pension
Period for payments under the plan (in years)		3 years
Maximum period for payments under the plan (in years)		10 years
Period for ending of payment obligation (in years)		20 years
Projected insolvency of the plan (in years)		19 years
Employer contributions to the plan per week through May 31, 2022	$ 18.03
Contribution to the plan assets (as a percent)			5.00%
Contributions		$ 158,000	$ 138,000