Employee Benefit Plans and Other Postretirement Benefits (Details) (USD $)	3 Months Ended			9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013		Sep. 30, 2014	Sep. 30, 2013
Defined Benefit Plan Disclosure [Line Items]
Net amortization of unrecognized amounts, Curtailment loss	$ 0	$ 3,132,000	[1]	$ 0	$ 10,908,000	[1]
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	5,828,000	5,825,000		17,428,000	18,322,000
Interest cost	11,507,000	4,269,000		34,400,000	12,250,000
Expected return on plan assets	(12,657,000)	(3,796,000)		(38,008,000)	(11,297,000)
Net amortization of unrecognized amounts, Prior service cost	1,641,000	163,000		4,922,000	3,284,000
Net amortization of unrecognized amounts, Actuarial loss	155,000	2,217,000		465,000	5,221,000
Net amortization of unrecognized amounts, Curtailment loss	0	3,132,000	[2]	0	10,908,000	[2]
Net periodic benefit cost	6,474,000	11,810,000		19,207,000	38,688,000
Decrease in the benefit obligation		(21,900,000)
Decrease in accumulated other comprehensive income (loss)		13,400,000
Deferred taxes		8,500,000
Pension Contributions [Abstract]
Contributions to pension plans in 2014				400,000
Postretirement Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost	392,000	515,000		1,177,000	1,545,000
Interest cost	311,000	311,000		933,000	934,000
Net amortization of unrecognized amounts, Prior service cost	(57,000)	(106,000)		(170,000)	(319,000)
Net amortization of unrecognized amounts, Actuarial loss	26,000	134,000		77,000	401,000
Net periodic benefit cost	$ 672,000	$ 854,000		$ 2,017,000	$ 2,561,000

[1] The three and nine months ended September 30, 2013, include $3.1 million and $10.9 million, respectively, of non-cash pension curtailment charges related to pension plan changes in which certain hourly corrugated plant and containerboard mill employees will transition from a defined benefit pension plan to a defined contribution (401k) plan.

[2] In June 2013, the United Steelworkers (“USW”) ratified a master labor agreement with PCA under which we froze certain USW-represented corrugated plant employees pension accruals under PCA’s hourly pension plan. Additionally, in September 2013, the USW ratified a master labor agreement with PCA under which we froze certain USW-represented containerboard mill employees pension accruals under PCA’s hourly pension plan. Following the pension freezes, affected USW-represented employees will transition to a defined contribution 401k plan. We recorded a $3.1 million and $10.9 million pre-tax pension curtailment charge related to the unrecognized prior service costs of employees impacted by the pension freezes during the three and nine months ended September 30, 2013, respectively. We also remeasured the hourly pension plan benefit obligation using current fair values of plan assets and current assumptions, resulting in a decrease in the benefit obligation of $21.9 million with a corresponding decrease in accumulated other comprehensive income (loss) of $13.4 million and deferred taxes of $8.5 million.