Commitments (Future rental commitments under leases) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014
Operating Leases, Future Minimum Payments Due [Abstract]
2014	$ 6,170
2015	8,013
2016	7,388
2017	6,761
2018	5,864
Thereafter	22,004
Total	$ 56,200

Amount of required minimum rental payments for leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 840

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-Section 55

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

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Amount of required minimum rental payments maturing in the next fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the fifth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the forth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the third fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing in the second fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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Amount of required minimum rental payments maturing after the fifth fiscal year following the latest fiscal year for operating leases having an initial or remaining non-cancelable letter-terms in excess of one year.

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