CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Statement of Comprehensive Income [Abstract]
Net income before allocation to noncontrolling interests	$ 193,569us-gaap_ProfitLoss	$ 220,951us-gaap_ProfitLoss	$ 217,821us-gaap_ProfitLoss
Other comprehensive income (loss), net of tax
Currency translation adjustment	(114,006)	2,850	4,481
Changes in pension and postretirement plan assets and benefit obligation, net of tax	(136,496)	76,488	(39,384)
Net current-period other comprehensive income	(250,502)	79,338	(34,903)
Comprehensive income (loss) before allocation to noncontrolling interests	(56,933)	300,289	182,918
Less: Noncontrolling interests in comprehensive income (loss)	(897)	(1,449)	(828)
Comprehensive income (loss) attributable to common shareholders	$ (57,830)us-gaap_ComprehensiveIncomeNetOfTax	$ 298,840us-gaap_ComprehensiveIncomeNetOfTax	$ 182,090us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income (loss) and other comprehensive income (loss), attributable to noncontrolling interests. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount after tax and reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

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The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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