Stock-Based Compensation (Activity Pertaining To Restricted Stock Awards) (Details) (USD $)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Ending Balance	614,133
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Beginning Balance	447,961	446,125	507,071
Weighted Average Grant Date Price, Beginning Balance	$ 47.44	$ 47.39	$ 47.46
Number of Shares, Granted	376,445	211,050	450,355
Weighted Average Grant Date Price, Granted	$ 47.37	$ 55.91	$ 41.09
Number of Shares, Vested	(220,788)	(190,262)	(496,497)
Weighted Average Grant Date Price, Vested	$ 45.66	$ 43.32	$ 47.09
Number of Shares, Forfeited	(14,091)	(18,952)	(14,804)
Weighted Average Grant Date Price, Forfeited	$ 45.37	$ 44.55	$ 44.25
Number of Shares, Ending Balance	589,527	447,961	446,125
Weighted Average Grant Date Price, Ending Balance	$ 48.11	$ 47.44	$ 47.39
Non-employee Directors [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of Shares, Beginning Balance	0
Weighted Average Grant Date Price, Beginning Balance	$ 0.00
Number of Shares, Granted	24,606
Weighted Average Grant Date Price, Granted	$ 40.23
Number of Shares, Vested	0
Weighted Average Grant Date Price, Vested	$ 0.00
Number of Shares, Forfeited	0
Weighted Average Grant Date Price, Forfeited	$ 0.00
Number of Shares, Ending Balance	24,606
Weighted Average Grant Date Price, Ending Balance	$ 40.23

The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.

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Period Type:	duration

- Definition

The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

+ References

+ Details

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- Definition

The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(2)(i)-(ii)

-URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(2)(b)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph b(2)(a)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details

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Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.

+ References

+ Details

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- Details

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Balance Type:	na
Period Type:	duration

- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

As of the balance sheet date, the weighted-average exercise price (at which grantees can acquire the shares reserved for issuance) for exercisable stock options that are fully vested or expected to vest.

+ References

+ Details

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Balance Type:	na
Period Type:	instant

- Definition

Weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated.

+ References

No definition available.

+ Details

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Data Type:	num:perShareItemType
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- Definition

Weighted average price at which grantees can acquire the shares reserved for issuance on stock options awarded.

+ References

No definition available.

+ Details

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