The cash inflow associated with the amount received from holders exercising their stock options. This item inherently excludes any excess tax benefit, which the entity may have realized and reported separately.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 123R

-Paragraph A240

-Subparagraph i

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 230

-SubTopic 10

-Section 45

-Paragraph 14

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3255-108585

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Financing Activities

-URI http://asc.fasb.org/extlink&oid=6513228

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 19

-Subparagraph 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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.

Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 95

-Paragraph 18

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (j)

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

+ Details

- 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+ Details

- Definition

Number of share options (or share units) exercised during the current period.

+ References+ Details

Stock options (Details 2) (USD $)	12 Months Ended
Stock options (Details 2) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Key Employee Stock Options [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period	9 years
Number of years after grant date that options granted expired	10 years
Employee Stock Option [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Share-based compensation arrangement by share-based payment award, award vesting period	3 years
Number of years after grant date that options granted expired	10 years
Director Stock Options [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Number of years after grant date that options granted expired	10 years
Stock options [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Share-based compensation arrangement by share-based payment award, options, outstanding, number, beginning balance	6,750
Share-based compensation arrangement by share-based payment award, options, outstanding, weighted average exercise price	$ 13.03
Share-based compensation arrangement by share-based payment award, options, exercises in period	(6,750)
Share-based compensation arrangements by share-based payment award, options, exercises in period, weighted average exercise price	$ 13.03
Share-based compensation arrangement by share-based payment award, options, outstanding, number, ending balance	0	6,750
Proceeds from stock options exercised	$ 88,000	$ 5,700,000	$ 5,000,000
Share-based compensation arrangement by share-based payment award, options, exercises in period, total intrinsic value	$ 60,000	$ 3,300,000	$ 2,600,000