Stock Options and Stock-Based Compensation (Details 3) (USD $)	3 Months Ended
Jun. 30, 2012
Stock options outstanding and exercisable
Number of Outstanding Options	651,093
Weighted Average Remaining Contractual Life	3 years 3 months 15 days
Outstanding Options-Weighted Average Exercise Price	$ 34.59
Exercisable Options-Number of Exercisable Options	325,797
Exercisable Options-Weighted Average Exercise Price	$ 27.27
Range of Exercise Price, $15.55 to $25.10 [Member]
Stock options outstanding and exercisable
Range of Exercise Price, lower limit	$ 15.55
Range of Exercise Price, upper limit	$ 25.10
Number of Outstanding Options	148,367
Weighted Average Remaining Contractual Life	2 years 1 month 2 days
Outstanding Options-Weighted Average Exercise Price	$ 19.66
Exercisable Options-Number of Exercisable Options	133,993
Exercisable Options-Weighted Average Exercise Price	$ 19.57
Range of Exercise Price, $25.11 to $30.97 [Member]
Stock options outstanding and exercisable
Range of Exercise Price, lower limit	$ 25.11
Range of Exercise Price, upper limit	$ 30.97
Number of Outstanding Options	181,964
Weighted Average Remaining Contractual Life	2 years 11 months 5 days
Outstanding Options-Weighted Average Exercise Price	$ 28.24
Exercisable Options-Number of Exercisable Options	120,136
Exercisable Options-Weighted Average Exercise Price	$ 28.19
Range of Exercise Price, $30.98 to $46.00 [Member]
Stock options outstanding and exercisable
Range of Exercise Price, lower limit	$ 30.98
Range of Exercise Price, upper limit	$ 46.00
Number of Outstanding Options	135,181
Weighted Average Remaining Contractual Life	4 years 3 months 26 days
Outstanding Options-Weighted Average Exercise Price	$ 39.33
Exercisable Options-Number of Exercisable Options	47,584
Exercisable Options-Weighted Average Exercise Price	$ 36.77
Range of Exercise Price, $46.01 to $52.76 [Member]
Stock options outstanding and exercisable
Range of Exercise Price, lower limit	$ 46.01
Range of Exercise Price, upper limit	$ 52.76
Number of Outstanding Options	186,391
Weighted Average Remaining Contractual Life	3 years 10 months 2 days
Outstanding Options-Weighted Average Exercise Price	$ 49.23
Exercisable Options-Number of Exercisable Options	24,084
Exercisable Options-Weighted Average Exercise Price	$ 46.68

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Weighted average exercise price as of the balance sheet date for those equity-based payment arrangements exercisable and outstanding.

+ References

+ Details

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- Definition

The floor of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph 64

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (g)

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

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- Definition

The number of shares reserved for issuance pertaining to the outstanding exercisable stock options as of the balance sheet date in the customized range of exercise prices for which the market and performance vesting condition has been satisfied.

+ 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)

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(iii)

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

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- Definition

The number of shares reserved for issuance pertaining to the outstanding stock options as of the balance sheet date for all option plans in the customized range of exercise prices.

+ 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)(1)(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(1)(a, 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.

+ Details

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- Definition

The weighted average price as of the balance sheet date at which grantees could acquire the underlying shares with respect to all outstanding stock options which are in the customized range of exercise prices.

+ References

+ Details

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- Definition

Weighted average remaining contractual term of outstanding stock options, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

+ Details

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- Definition

The ceiling of a customized range of exercise prices for purposes of disclosing shares potentially issuable under outstanding stock option awards on all stock option plans and other required information pertaining to awards in the customized range.

+ References

+ Details

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