Quarterly Financial Data - Summary of Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2017	[1]	Sep. 30, 2017	[2]	Jun. 30, 2017	[3]	Mar. 31, 2017	[4]	Dec. 31, 2016	[5]	Sep. 30, 2016	[6]	Jun. 30, 2016	[7]	Mar. 31, 2016	[8]	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 1,684.3		$ 1,640.1		$ 1,584.0		$ 1,536.5		$ 1,476.6		$ 1,484.0		$ 1,417.4		$ 1,401.0		$ 6,444.9	$ 5,779.0	$ 5,741.7
Gross profit	371.7		397.3		364.6		338.5		327.1		329.5		320.1		299.0		1,472.2	1,275.7	1,208.0
Operating Income (Loss)	252.0		242.3		233.8		203.1		192.9		206.4		200.2		180.8		931.2	780.3	750.0
Net income	$ 268.9		$ 139.1		$ 143.2		$ 117.4		$ 110.6		$ 119.4		$ 115.9		$ 103.7		$ 668.6	$ 449.6	$ 436.8
Basic	$ 2.85		$ 1.47		$ 1.52		$ 1.25		$ 1.17		$ 1.27		$ 1.23		$ 1.09		$ 7.09	$ 4.76	$ 4.47
Diluted	2.84		1.47		1.52		1.24		1.17		1.26		1.23		1.09		7.07	4.75	$ 4.47
Stock price - high	121.38		119.43		113.52		96.87		88.41		82.77		71.31		62.67		121.38	88.41
Stock price - low	$ 108.49		$ 105.81		$ 89.73		$ 84.01		$ 78.03		$ 65.12		$ 58.44		$ 44.32		$ 84.01	$ 44.32

[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).