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.

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)(iii)

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

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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

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

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

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

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)(1)(i)-(ii)

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

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Weighted average price 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

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- Definition

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

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 10

-Section 50

-Paragraph 2

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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 Accounting Standards Codification

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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.

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Share-based compensation - Schedule of management and director options outstanding (Details) (USD $)	9 Months Ended		12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding (in shares)	11,269,911.000		10,981,075.000	10,956,838.000	0
Options outstanding, weighted average exercise price (in dollars per share)	$ 13.40		$ 13.23	13.20	$ 0.00
Remaining contractual life	7 years 4 months 24 days	6 years 6 months
Management and director options
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Options outstanding (in shares)	11,269,911.000		10,981,075.000
Options outstanding, weighted average exercise price (in dollars per share)	$ 13.40		$ 13.23
Remaining contractual life			8 years 0 months 22 days	9 years
Options exercisable (in shares)	3,791,311.000		3,120,613.000
Options exercisable, weighted average exercise price (in dollars per share)	$ 13.22		$ 13.20
Management and director options \| $10.00-$10.89
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 10.00		$ 10.00
Exercise price, upper limit (in dollars per share)	$ 10.89		$ 10.89
Options outstanding (in shares)	6,528,647		6,588,647
Options outstanding, weighted average exercise price (in dollars per share)	$ 10.03		$ 10.03
Remaining contractual life			8 years 0 months 22 days
Options exercisable (in shares)	2,226,787		1,872,367
Options exercisable, weighted average exercise price (in dollars per share)	$ 10.02		$ 10.00
Management and director options \| $16.00-$16.89
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 15.05		$ 16.00
Exercise price, upper limit (in dollars per share)	$ 16.89		$ 16.89
Options outstanding (in shares)	2,405,516		2,196,214
Options outstanding, weighted average exercise price (in dollars per share)	$ 15.94		$ 16.03
Remaining contractual life			8 years 0 months 22 days
Options exercisable (in shares)	782,262		624,123
Options exercisable, weighted average exercise price (in dollars per share)	$ 16.02		$ 16.00
Management and director options \| $20.00-$20.89
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Line Items]
Exercise price, lower limit (in dollars per share)	$ 20.00		$ 20.00
Exercise price, upper limit (in dollars per share)	$ 25.05		$ 20.89
Options outstanding (in shares)	2,335,748		2,196,214
Options outstanding, weighted average exercise price (in dollars per share)	$ 20.21		$ 20.03
Remaining contractual life			8 years 0 months 22 days
Options exercisable (in shares)	782,262		624,123
Options exercisable, weighted average exercise price (in dollars per share)	$ 20.02		$ 20.00