Comprehensive Income (Components of Comprehensive Income) (Details) (USD $) In Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
Comprehensive Income
Net income	$ 24,836	$ 27,002	$ 45,283	$ 45,227
Unrealized foreign currency translation adjustment	304	(764)	1,042	129
Unrealized (loss) gain - interest rate swaps, net of tax	1,664	(565)	3,900	(1,877)
Post-retirement medical plan termination, net of tax		(834)		(834)
Total comprehensive income	$ 26,804	$ 24,839	$ 50,225	$ 42,645

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 reporting entity. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, but excludes any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

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+ Details

- Definition

The increase (decrease) in accumulated comprehensive income during the period related to pension and other postretirement benefit plans, after tax. While for technical reasons this element has no balance attribute, the default assumption is a credit balance consistent with its label.

+ References+ Details

- Definition

Change in the balance sheet adjustment that results from the process of translating subsidiary financial statements and foreign equity investments into functional currency of the reporting entity for the period being reported, net of tax. If an entity's functional currency is a foreign currency, translation adjustments result from the process of translating that entity's financial statements into the reporting currency. Includes gain (loss) on foreign currency forward exchange contracts. Includes foreign currency transactions designated as hedges of net investment in a foreign entity and intercompany foreign currency transactions that are of a long-term nature, when the entities to the transaction are consolidated, combined, or accounted for by the equity method in the reporting enterprise's financial statements. Includes the gain (loss) on a derivative instrument or nonderivative financial instrument that may give rise to a foreign currency transaction gain (loss) and that have been designated and have qualified as hedging instruments for hedges of the foreign currency exposure of a net investment in a foreign operation.

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+ Details

- Definition

Change in accumulated gains and losses from derivative instrument designated and qualifying as the effective portion of cash flow hedges, net of tax effect. The after tax effect change includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

+ References

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+ Details

- Definition

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

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+ Details