Debt (Details) | Jun. 30, 2014 | Dec. 31, 2013 | Jun. 30, 2014 | Jun. 24, 2014 | Jun. 16, 2014 | Dec. 31, 2013 | Jul. 16, 2014 | Sep. 27, 2013 | Jun. 30, 2014 | Dec. 31, 2013 | Jun. 30, 2014 | Jun. 30, 2014 | Dec. 31, 2013 | Dec. 31, 2013 | Sep. 27, 2013 | Sep. 27, 2013 | Sep. 27, 2013 | Dec. 31, 2013 | Dec. 31, 2013 | Sep. 27, 2013 | Dec. 31, 2013 | Jun. 30, 2014 | Dec. 31, 2013 | Jun. 30, 2014 | Dec. 31, 2013 | Jun. 30, 2014 | Dec. 31, 2013 | Jun. 30, 2014 | Dec. 31, 2013 | Jun. 30, 2014 | Dec. 31, 2013 |
In Thousands, unless otherwise specified | USD ($) | USD ($) | Convertible Debt [Member] | Convertible Debt [Member] | Convertible Debt [Member] | Convertible Debt [Member] | Convertible Debt [Member] | Revolving Credit Agreement [Member] | Revolving Credit Agreement [Member] | Revolving Credit Agreement [Member] | Revolving Credit Agreement [Member] | Revolving Credit Agreement [Member] | Revolving Credit Agreement [Member] | Revolving Credit Agreement [Member] | Revolving Credit Agreement [Member] | Revolving Credit Agreement [Member] | Revolving Credit Agreement [Member] | Revolving Credit Agreement [Member] | Revolving Credit Agreement [Member] | Revolving Credit Agreement [Member] | Revolving Credit Agreement [Member] | Lines of Credit and Overdrafts [Member] | Lines of Credit and Overdrafts [Member] | Foreign Bank Borrowings [Member] | Foreign Bank Borrowings [Member] | Lines of Credit [Member] | Lines of Credit [Member] | Bank Overdrafts [Member] | Bank Overdrafts [Member] | Capital Lease Obligations [Member] | Capital Lease Obligations [Member] |
| | | 3.375% Convertible Notes [Member] | 3.375% Convertible Notes [Member] | 3.375% Convertible Notes [Member] | 3.375% Convertible Notes [Member] | 3.375% Convertible Notes [Member] | USD ($) | USD ($) | USD ($) | Euro Member Countries, Euro | Euro Member Countries, Euro | Euro Member Countries, Euro | Euro Member Countries, Euro | London Interbank Offered Rate (LIBOR) [Member] | London Interbank Offered Rate (LIBOR) [Member] | EUR (€) | Minimum [Member] | Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Adjusted for Certain Acquisitons [Member] | USD ($) | USD ($) | USD ($) | USD ($) | USD ($) | USD ($) | USD ($) | USD ($) | USD ($) | USD ($) |
| | | USD ($) | USD ($) | USD ($) | USD ($) | Subsequent Event [Member] | | | | USD ($) | EUR (€) | USD ($) | EUR (€) | Minimum [Member] | Maximum [Member] | | USD ($) | | | Maximum [Member] | | | | | | | | | | |
| | | | | | | USD ($) | | | | | | | | | | | | | | | | | | | | | | | | |
Debt Instrument [Line Items] | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Carrying amount of debt | ' | ' | $55,636 | ' | ' | $55,636 | ' | ' | $498,842 | $487,920 | $117,942 | € 86,420 | $157,320 | € 114,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | $135 | $405 | ' | ' | ' | ' | $4,038 | $3,120 |
Fair value of debt | 601,031 | 563,886 | 75,845 | ' | ' | 76,569 | ' | ' | 508,354 | 482,431 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 12,265 | 1,074 | 136 | 410 | ' | ' | ' | ' | 4,431 | 3,402 |
Unamortized debt discount | ' | ' | 0 | ' | ' | -731 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Borrowings under lines of credit and overdrafts | 12,265 | 1,074 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 12,265 | 1,074 | ' | ' | 10,500 | 1,000 | 1,765 | 74 | ' | ' |
Total debt, net of unamortized discounts | 570,916 | 547,424 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Less current maturities | -68,971 | -57,083 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Long-term debt | 501,945 | 490,341 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Stated interest rate | ' | ' | 3.38% | ' | ' | ' | ' | ' | 1.47% | 1.36% | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Convertible debt | ' | ' | ' | 55,412 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Convertible note repurchases, par value | ' | ' | ' | ' | 224 | ' | 32,875 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Line of credit facility, maximum borrowing capacity | ' | ' | ' | ' | ' | ' | ' | 750,000 | ' | ' | ' | ' | ' | ' | ' | ' | 500,000 | ' | ' | ' | ' | ' | ' | ' | ' | 40,000 | ' | ' | ' | ' | ' |
Line of credit facility with accordian feature, maximum borrowing capacity | ' | ' | ' | ' | ' | ' | ' | 1,000,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Variable rate basis | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 'LIBOR | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Variable basis spread | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 1.10% | 1.70% | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Payments of debt issuance costs | ' | ' | ' | ' | ' | ' | ' | 1,261 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Remaining borrowing capacity | ' | ' | ' | ' | ' | ' | ' | ' | 251,158 | 262,080 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Debt covenant ratio of senior debt to EBITDA | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 3.25 | ' | 3.5 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Debt covenant ratio of total debt to EBITDA | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 4 | ' | 4.25 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Debt covenant ratio of EBITDA to cash interest expense | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 4.25 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Debt covenant, threshold price of acquisition permitting higher ratio limits | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | $150,000 | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Line of credit, interest rate at period end | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | 1.15% | 2.13% | ' | ' | ' | ' |
Repayment period | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | '1 month | ' | '2 days | ' | ' | ' |
Days Required for Closing Stock Price to be Greater or Equal to Threshold Percentage of Conversion Price | ' | ' | '20 days | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Total Measurement Days for Closing Stock Price to be Greater or Equal to Threshold Percentage of Conversion Price | ' | ' | '30 days | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |
Minimum Ratio Of Stock Price To Conversion Price For Conversion | ' | ' | 130.00% | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' | ' |