Segment Information (Parenthetical) (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended																12 Months Ended
		Sep. 30, 2015	Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2016		Sep. 30, 2016		Jun. 30, 2016		Mar. 31, 2016		Dec. 31, 2017		Dec. 31, 2016		Dec. 31, 2015
Segment Reporting Information [Line Items]
Operating Income (Loss)			$ 252.0	[1]	$ 242.3	[2]	$ 233.8	[3]	$ 203.1	[4]	$ 192.9	[5]	$ 206.4	[6]	$ 200.2	[7]	$ 180.8	[8]	$ 931.2		$ 780.3		$ 750.0
Acquisition and integration related costs	[9],[10],[11]																		0.8		3.3		12.9
Hexacomb working capital adjustment	[12]																		2.3
Interest expense, net																			(102.6)	[13]	(91.8)		(85.5)
Write-Off of Deferred Financing Costs
Segment Reporting Information [Line Items]
Interest expense, net			1.8																(1.8)
TimBar Corporation
Segment Reporting Information [Line Items]
Operating Income (Loss)							(0.2)		0.2		(1.2)		(2.9)		(0.3)
Mill at St. Helens, Oregon
Segment Reporting Information [Line Items]
Gain on sale of land, buildings, and equipment		$ 6.7																					6.7	[14]
Deridder Mill
Segment Reporting Information [Line Items]
Restructuring	[15]																						7.1
Wallula, Washington Mill
Segment Reporting Information [Line Items]
Operating Income (Loss)			$ (8.0)		$ (25.3)						(2.7)
Restructuring charges																			$ 23.1
High-performance of virgin kraft linerboard machine percentage			100.00%		100.00%														100.00%
Facilities closure costs	[16]																				0.6
Restructuring	[17]																		$ (23.1)
Packaging
Segment Reporting Information [Line Items]
Operating Income (Loss)																			943.7	[18]	711.0	[19]	714.9	[20]
Acquisition and integration related costs																			1.7
Facilities closure costs																					10.2
Packaging | TimBar Corporation
Segment Reporting Information [Line Items]
Acquisition-related costs																					4.2
Packaging | Boise Inc.
Segment Reporting Information [Line Items]
Operating Income (Loss)																							4.1
Packaging | Deridder Mill
Segment Reporting Information [Line Items]
Property damages and business interruption insurance			$ 5.0																5.0
Packaging | Hexacomb Europe and Mexico
Segment Reporting Information [Line Items]
Acquisition and integration related costs																			1.6
Paper
Segment Reporting Information [Line Items]
Operating Income (Loss)																			61.5	[21]	138.1	[22]	112.5	[23]
Facilities closure costs																			0.4		1.7
Paper | Wallula, Washington Mill
Segment Reporting Information [Line Items]
Restructuring charges																			$ 33.4
High-performance of virgin kraft linerboard machine percentage																			100.00%
Restructuring																					2.7
Corporate and Other
Segment Reporting Information [Line Items]
Operating Income (Loss)																			$ (74.0)	[24]	(68.9)	[25]	(77.4)	[26]
Facilities closure costs																			1.0
Corporate and Other | TimBar Corporation
Segment Reporting Information [Line Items]
Acquisition-related costs																					$ 0.3
Corporate and Other | Boise Inc.
Segment Reporting Information [Line Items]
Operating Income (Loss)																							9.3
Corporate and Other | Hexacomb Europe and Mexico
Segment Reporting Information [Line Items]
Hexacomb working capital adjustment																			0.7
Corrugated Products Facility Closure
Segment Reporting Information [Line Items]
Operating Income (Loss)			$ 7.6		$ (0.9)		$ (0.3)		$ (0.6)		$ (4.5)		$ (2.0)		$ (2.6)		$ (2.8)
Corrugated Products Facility Closure | Packaging
Segment Reporting Information [Line Items]
Operating Income (Loss)																			7.2
Timberland | Packaging
Segment Reporting Information [Line Items]
Operating Income (Loss)																			$ 2.0
Other Restructuring | Packaging
Segment Reporting Information [Line Items]
Operating Income (Loss)																							$ 2.0

[1] Includes $7.6 million of income primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, a paper administration facility, and a corporate administration facility ($4.7 million after-tax or $0.05 per diluted share) and $0.9 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.5 million after-tax or $0.01 per diluted share), and $8.0 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($4.6 million after-tax or $0.05 per diluted share). Also includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing ($1.1 million after-tax or $0.01 per diluted share), $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold ($1.2 million after-tax or 0.01 per diluted share), and $122.1 million of estimated income tax benefit related to the enactment in December 2017 of the Tax Cuts and Jobs Act (H.R.1) primarily for the re-measurement of our net deferred tax liability as a result of the reduction in the U.S. corporate income tax rate ($1.29 per diluted share).

[2] Includes $0.9 million of charges related to the closure of corrugated products facilities, a paper administration facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($0.6 million after-tax or $0.01 per diluted share) and $0.5 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions ($0.3 million after-tax or $0.0 per diluted share). Also includes $25.3 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine ($15.5 million after-tax or $0.16 per diluted share) and $3.3 million of tax expense for the change in value of deferred taxes as a result of an internal legal entity consolidation that will simplify future operating activities ($0.04 per diluted share).

[3] Includes $0.3 million of charges related to the closure of corrugated products facilities ($0.3 million after-tax or $0.0 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 after-tax or $0.0 per diluted share).

[4] Includes $0.6 million of charges related to the closure of corrugated products facilities and lump sum settlement of a multiemployer pension plan withdrawal liability for one of corrugated products facilities ($0.4 million after-tax or $0.1 per diluted share) and $0.2 million of charges related to TimBar Corporation and Columbus Container integration costs ($0.1 million after-tax or $0.0 per diluted share). Also includes $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill ($3.1 million after-tax or $0.03 per diluted share) and $2.3 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico ($1.4 million after-tax or $0.01 per diluted share).

[5] Includes $4.5 million of charges related to the closure of a corrugated products facility and a paper products facility ($2.9 million after-tax or $0.03 per diluted share), $2.7 million of costs related to ceased production of softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine ($1.8 million after-tax or $0.02 per diluted share), and $1.2 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($0.8 million after-tax or $0.01 per diluted share).

[6] Includes $2.0 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.4 million after-tax or $0.02 per diluted share) and $2.9 million of charges related to the TimBar Corporation and Columbus Container acquisitions and integration ($1.9 million after-tax or $0.02 per diluted share).

[7] Includes $2.6 million of charges related to the closure of corrugated products facilities, a paper products facility, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities ($1.6 million after-tax or $0.02 per diluted share) and $0.3 million of charges related to the TimBar Corporation acquisition and integration ($0.2 million after-tax or $0.0 per diluted share).

[8] Includes $2.8 million of charges related to the closure of a corrugated products facility and a paper products facility ($1.9 million after-tax or $0.02 per diluted share).

[9] For 2015, includes Boise acquisition integration-related and other costs, which primarily relate to severance, retention, travel, and professional fees.

[10] For 2016, includes charges related to the acquisition and integration of TimBar Corporation.

[11] For 2017, includes charges related to the Sacramento Container Corporation acquisition and integration costs related to other recent acquisitions.

[12] Includes income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico.

[13] Includes $1.8 million of expense related to the write-off of deferred debt issuance costs in connection with the December 2017 debt refinancing.

[14] Includes a gain related to the sale of the remaining land, buildings, and equipment at our paper mill site in St. Helens, Oregon where we ceased paper production in December 2012.

[15] Includes $7.1 million of income from vendor settlements related to our restructuring activities at our DeRidder, Louisiana mill.

[16] Includes costs related to ceased softwood market pulp operations at our Wallula, Washington mill and the permanent shutdown of the No. 1 machine.

[17] Includes $23.1 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine.

[18] (a)Includes the following: $7.2 million of income, net, primarily related to the sale of land corresponding to the closure of a corrugated products facility, partially offset by closure costs related to corrugated products facilities, and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities. $1.7 million of charges related to the Sacramento Container acquisition and integration costs related to other recent acquisitions. $2.0 million gain related to the expiration of a repurchase option corresponding to timberland previously sold. $1.6 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico. $5.0 million of costs for the property damage and business interruption insurance deductible corresponding to the February 2017 explosion at our DeRidder, Louisiana mill.

[19] Includes $10.2 million of closure costs related to corrugated product facilities and a lump sum settlement of a multiemployer pension plan withdrawal liability for one of our corrugated products facilities and $4.2 million of acquisition-related costs for the TimBar Corporation and Columbus Container acquisitions.

[20] Includes net charges of $2.0 million primarily related to restructuring activities at our mill in DeRidder, Louisiana and $4.1 million of Boise acquisition integration-related and other costs.

[21] Includes $33.4 million of charges related to our determination to discontinue production of uncoated free sheet and coated one-side grades at the Wallula, Washington mill in the second quarter of 2018 and convert the No. 3 paper machine to a high-performance 100% virgin kraft linerboard machine and $0.4 million of charges related to the closure costs of a paper administration facility.

[22] Includes $2.7 million of costs related to ceased softwood market pulp operations at our Wallula, Washington mill and the permanent shut down of the No.1 machine and $1.7 million of closure costs related to a paper products facility.

[23] In September 2015, we sold the remaining land, buildings, and equipment at our paper mill site in St. Helens, Oregon where we ceased paper production in December 2012. We recorded a $6.7 million gain on the sale.

[24] Includes $1.0 million of charges related to the closure costs of a corporate administration facility and $0.7 million of income related to a working capital adjustment from the April 2015 sale of our Hexacomb corrugated manufacturing operations in Europe and Mexico.

[25] Includes $0.3 million of acquisition-related costs related to the TimBar Corporation acquisition.

[26] Includes $9.3 million of Boise acquisition integration-related and other costs. These costs primarily relate to professional fees, severance, retention, relocation, travel, and other integration-related costs.