Cash and stock-based compensation plans (Details 6) (Stock Option Plan 2006 - Directors and Executives [Member], USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Stock Option Plan 2006 - Directors and Executives [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Options Outstanding	49,804	180,154	207,706
Forfeited Options	0	0	0
Exercised Options	(49,804)	(130,350)	(27,552)
Options Outstanding	0	49,804	180,154
Outstanding weighted average exercise price	$ 16.34	$ 16.34	$ 16.34
Forfeited Weighted average exercise price	$ 0	$ 0	$ 0
Exercised Weighted average exercise price	$ 16.34	$ 16.34	$ 16.34
Outstanding weighted average exercise price	$ 0	$ 16.34	$ 16.34
Outstanding Weighted Average remaining contractual term	0 years
Outstanding Aggregate intrinsic value	$ 0

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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 Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (c)(1)(iv)(3)

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Amount by which the current fair value of the underlying stock exceeds the exercise price of options outstanding.

+ References

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Number of options outstanding, including both vested and non-vested options.

+ References

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

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

+ References

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- Definition

Weighted average price at which option holders acquired shares when converting their stock options into shares.

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

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No definition available.

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

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

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