CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net Income	$ 39,644	$ 64,167	$ 87,541	$ 96,433
Other Comprehensive Income
Net Changes in Fair Value of Cash Flow Hedges:	697	700	1,672	2,156
Supplemental Executive Retirement Plan (SERP) Benefit Amortization:	25	68	74	205
Total Other Comprehensive Income, Net of Taxes	722	768	1,746	2,361
Total Comprehensive Income	$ 40,366	$ 64,935	$ 89,287	$ 98,794

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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-Name Accounting Standards Codification

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Net income after adjustments for dividends on preferred stock (declared in the period) and/or cumulative preferred stock (accumulated for the period).

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Amount after tax of reclassification adjustment from accumulated other comprehensive (income) loss for prior service cost (credit) related to pension and other postretirement benefit plans.

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Amount after tax and reclassification adjustments, of increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss).

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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