Accumulated Other Comprehensive Loss (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended			12 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013		Jun. 30, 2012	Dec. 31, 2012
Foreign currency translation adjustments	$ 21,179		$ 21,179			$ 38,829
Joint venture cash flow hedges	(2,197)		(2,197)			(3,628)
Unrecognized losses of employee benefit plans, net of tax	(135,893)		(135,893)			(144,580)
Total	(116,911)		(116,911)			(109,379)
Other comprehensive income before reclassifications - Foreign currency translation gains			(17,650)	[1]
Other comprehensive income before reclassifications - New Zealand joint venture cash flow hedge			(728)
Other comprehensive income before reclassifications - Unrecognized components of employee benefit plans, net of tax			530
Other comprehensive income before reclassifications - Total			(17,848)
Amounts reclassified from accumulated other comprehensive income - Foreign currency translation gains			0
Amounts reclassified from accumulated other comprehensive income - New Zealand joint venture cash flow hedges			2,159
Amounts reclassified from accumulated other comprehensive income - Unrecognized components of employee benefit plans, net of tax			8,157	[2]
Amounts reclassified from accumulated other comprehensive income - Total			10,316
Net other comprehensive income - Foreign currency translation adjustment	(28,201)	(8,081)	(27,226)		(2,255)	4,352
Net other comprehensive income - New Zealand joint venture cash flow hedges	222	(1,998)	775		(793)	213
Net other comprehensive income - Gain from pension and postretirement plans, net of income tax	3,717	3,401	8,687		6,541	(496)
Net other comprehensive income, net of tax			(7,532)
Gain on New Zealand Joint Venture Cash Flow Hedge Reclassified from AOCI			2,159
Parent [Member]
Net other comprehensive income - Foreign currency translation adjustment			(17,650)
Net other comprehensive income - New Zealand joint venture cash flow hedges			1,431
Net other comprehensive income - Gain from pension and postretirement plans, net of income tax			$ 8,687

[1] The loss is due to a six cent decrease in the New Zealand dollar exchange rate.

[2] These accumulated other comprehensive income components are included in the computation of net periodic pension cost. See Note 15 — Employee Benefit Plans for additional information.