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Fair Value Measurements - Additional Information (Details)
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3 Months Ended | 3 Months Ended | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
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Mar. 31, 2014
USD ($)
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Mar. 31, 2013
USD ($)
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Mar. 31, 2014
Credit Agreement
USD ($)
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Dec. 31, 2013
Credit Agreement
USD ($)
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Mar. 31, 2014
Receivables securitization facility
USD ($)
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Dec. 31, 2013
Receivables securitization facility
USD ($)
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Mar. 31, 2014
Senior notes
USD ($)
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Dec. 31, 2013
Senior notes
USD ($)
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Mar. 31, 2013
ECP 2012 Contingent Payment
USD ($)
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Mar. 31, 2013
ECP 2012 Contingent Payment
GBP (£)
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Jun. 30, 2014
Subsequent Event
ECP 2012 Contingent Payment
USD ($)
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Jun. 30, 2014
Subsequent Event
ECP 2012 Contingent Payment
GBP (£)
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Apr. 02, 2014
Subsequent Event
ECP 2013 Contingent Payment
USD ($)
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| Fair Value Measurements | |||||||||||||
| Maximum payment under contingent consideration agreement | £ 25,000,000 | $ 30,000,000 | |||||||||||
| Contingent consideration payments | 2,006,000 | 37,768,000 | 33,900,000 | 22,400,000 | 44,800,000 | 26,900,000 | |||||||
| Contingent consideration other settlements | 3,900,000 | 2,600,000 | 5,100,000 | 3,100,000 | |||||||||
| (Gains) Losses related to contingent consideration obligations outstanding at period-end | 700,000 | (800,000) | |||||||||||
| Borrowings under credit agreement, carrying value | 992,200,000 | 672,600,000 | |||||||||||
| Borrowings under receivable securitization facility, carrying value | 80,000,000 | 80,000,000 | 0 | ||||||||||
| Debt instrument, fair value | 572,000,000 | ||||||||||||
| Debt instrument, carrying amount | $ 600,000,000 | $ 600,000,000 | |||||||||||