Subsequent Events - United States Postal Service Settlement - Additional Information (Details) - USPS [Member] - Forecast [Member] - USD ($) $ in Millions			3 Months Ended
Feb. 19, 2021	Jan. 19, 2021	Dec. 31, 2020
Subsequent Event [Line Items]
Payments for transportation settlements	$ 17.5	$ 7.1
Additional settlement payment including rate adjustments under settlement agreement			$ 3.8

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

No definition available.

Name:	us-gaap_SubsequentEventLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration