US Treasury Grant - Additional Information (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	12 Months Ended
Apr. 11, 2012	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Disclosure U S Treasury Grant Additional Information [Abstract]
Treasury grant proceeds	$ 57.4pkg_ProceedsFromGovernmentGrant	$ 0pkg_ProceedsFromGovernmentGrant	$ 0pkg_ProceedsFromGovernmentGrant	$ 57.4pkg_ProceedsFromGovernmentGrant
Annual amortization of U.S. treasury grant proceeds		$ 3.2

Proceeds from U.S. treasury grant are amortized ratably over the estimated useful lives of the related equipment, each year.

No definition available.

Name:	pkg_AmortizationofU.S.TreasuryGrantProceeds
Namespace Prefix:	pkg_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration