CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
NET INCOME	$ 68,134	$ 49,517
Pension and other postretirement benefit adjustments, net of income taxes of $1,953 and $1,825, respectively:
Amortization of net loss	4,412	4,087
Amortization of transition obligation	0	77
Amortization of prior service cost	(784)	(775)
OTHER COMPREHENSIVE INCOME	3,628	3,389
COMPREHENSIVE INCOME	$ 71,762	$ 52,906

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the economic entity, including both controlling (parent) and noncontrolling interests. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, including any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

+ References+ Details

The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Glossary Other Comprehensive Income

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-Name Emerging Issues Task Force (EITF)

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Reference 12: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-Glossary Net Income

-URI http://asc.fasb.org/extlink&oid=6518256

Reference 13: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-Name Regulation S-X (SX)

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-Section 04

-Paragraph 20

-Article 9

+ Details

- Definition

The adjustment out of other comprehensive income for prior service costs recognized as a component of net period benefit cost during the period, after tax.

+ References

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+ Details

- Definition

Tax effect on adjustment out of other comprehensive income for prior service costs recognized as a component of net period benefit cost during the period.

+ References

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+ Details

- Definition

This element represents Other Comprehensive Income or Loss, Net of Tax, for the period attributable to the parent entity. Includes deferred gains or losses on qualifying hedges, unrealized holding gains or losses on available-for-sale securities, minimum pension liability, and cumulative translation adjustment.

+ References

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+ Details

- Definition

The adjustment out of other comprehensive income for the net transition asset or obligation recognized as a component of net periodic benefit cost during the period, after tax.

+ References+ Details