Schedule of Purchase Commitments (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012
Long-term Purchase Commitment [Line Items]
2013	$ 5,960
2014	4,903
2015	1,486
2016	1,486
2017	1,486
Thereafter	15,980
Total	$ 31,301

The minimum amount the entity agreed to spend under the long-term purchase commitment after the fifth year after the balance sheet date.

No definition available.

Name:	pkg_LongTermPurchaseCommitmentAmountDueThereafter
Namespace Prefix:	pkg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The minimum amount the entity agreed to spend under the long-term purchase commitment in the fifth year after the balance sheet date.

No definition available.

Name:	pkg_LongTermPurchaseCommitmentAmountDueWithinFiveYears
Namespace Prefix:	pkg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The minimum amount the entity agreed to spend under the long-term purchase commitment in the fourth year after the balance sheet date.

No definition available.

Name:	pkg_LongTermPurchaseCommitmentAmountDueWithinFourYears
Namespace Prefix:	pkg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The minimum amount the entity agreed to spend under the long-term purchase commitment in the first year after the balance sheet date.

No definition available.

Name:	pkg_LongTermPurchaseCommitmentAmountDueWithinOneYear
Namespace Prefix:	pkg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The minimum amount the entity agreed to spend under the long-term purchase commitment in the third year after the balance sheet date.

No definition available.

Name:	pkg_LongTermPurchaseCommitmentAmountDueWithinThreeYears
Namespace Prefix:	pkg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The minimum amount the entity agreed to spend under the long-term purchase commitment in the second year after the balance sheet date.

No definition available.

Name:	pkg_LongTermPurchaseCommitmentAmountDueWithinTwoYears
Namespace Prefix:	pkg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

The total of contractually required payments on long-term purchase commitments.

No definition available.

Name:	pkg_LongTermPurchaseCommitmentFutureMinimumPaymentsDue
Namespace Prefix:	pkg_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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