Stock Compensation (Summary Of Stock Option Activity) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	6 Months Ended
Jun. 30, 2011 years days months
Stock Compensation
Number of Options, Outstanding at beginning of period	577,816
Number of Options, Granted	14,000
Number of Options, Exercised	(24,600)
Number of Options, Forfeited
Number of Options, Outstanding at end of period	567,216
Number of Options, Exercisable at end of period	303,216
Weighted Average Exercise Price, Outstanding at beginning of period	$ 48.95
Weighted Average Exercise Price, Granted	$ 60.66
Weighted Average Exercise Price, Exercised	$ 42.67
Weighted Average Exercise Price, Forfeited
Weighted Average Exercise Price, Outstanding at end of period	$ 49.51
Weighted Average Exercise Price, Exercisable at end of period	$ 46.52
Weighted Average Remaining Contract Life, Outstanding, in years	6.18
Weighted Average Remaining Contract Life, Exercisable, in years	4.22
Aggregate Intrinsic Value, Outstanding	$ 3,884
Aggregate Intrinsic Value, Exercisable	$ 3,065

Name:	us-gaap_EmployeeServiceShareBasedCompensationAggregateDisclosuresAbstract
Namespace Prefix:	us-gaap
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

The total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices of vested portions of options outstanding and currently exercisable under the option plan as of the balance-sheet date.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableIntrinsicValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The number of shares into which fully or partially vested stock options outstanding as of the balance-sheet date can be currently converted under the option plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(1)(c), d(2)

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber
Namespace Prefix:	us-gaap
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(1)(c)

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice
Namespace Prefix:	us-gaap
Data Type:	us-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted average period between the balance-sheet date and expiration for all vested portions of options outstanding and currently exercisable (or convertible) under the plan, which may be expressed in a decimal value for number of years.

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm
Namespace Prefix:	us-gaap
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average price at which option holders acquired shares when converting their stock options into shares under the plan during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(1)(e)

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice
Namespace Prefix:	us-gaap
Data Type:	us-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(1)(f)

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriod
Namespace Prefix:	us-gaap
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average price at which grantees could have acquired the underlying shares with respect to stock options that were terminated during the reporting period due to noncompliance with plan terms during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(1)(f)

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsForfeituresInPeriodWeightedAverageExercisePrice
Namespace Prefix:	us-gaap
Data Type:	us-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The quantity of shares issuable on stock options awarded under the plan during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(1)(d)

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriod
Namespace Prefix:	us-gaap
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

The weighted average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on stock options awarded under the plan during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(1)(d)

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageExercisePrice
Namespace Prefix:	us-gaap
Data Type:	us-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The total dollar difference between fair values of the underlying shares reserved for issuance and exercise prices pertaining to options outstanding under the plan as of the balance-sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph d(1)

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingIntrinsicValue
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The number of shares reserved for issuance under stock option agreements awarded under the plan that validly exist and are outstanding as of the balance-sheet date, including vested options.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(1)(a)

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(1)(b)

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
Namespace Prefix:	us-gaap
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted average price as of the beginning of the year at which grantees can acquire the shares reserved for issuance under the stock option plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph b(1)(a)

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice
Namespace Prefix:	us-gaap
Data Type:	us-types:perShareItemType
Balance Type:	na
Period Type:	instant

- Definition

The weighted average period between the balance-sheet date and expiration for all awards outstanding under the plan, which may be expressed in a decimal value for number of years.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Statement of Financial Accounting Standard (FAS)
-Number 123R
-Paragraph A240
-Subparagraph a

+ Details

Name:	us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm
Namespace Prefix:	us-gaap
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of shares issued during the period as a result of the exercise of stock options.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher AICPA
-Name Accounting Principles Board Opinion (APB)
-Number 12
-Paragraph 10

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 04
-Article 3

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Regulation S-X (SX)
-Number 210
-Section 02
-Paragraph 29, 30
-Article 5

+ Details

Name:	us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised
Namespace Prefix:	us-gaap
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration