Consolidated Balance Sheets Balance Sheet Parenthetical In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015 USD ($)	Mar. 31, 2015 EUR (€)	Dec. 31, 2014 USD ($)	Dec. 31, 2014 EUR (€)
Allowance for Doubtful Accounts Receivable, Current	$ 4,228		$ 3,397
Common Stock, Par or Stated Value Per Share		€ 0.02		€ 0.02
Common Stock, Shares Authorized	200,000,000	200,000,000	200,000,000	200,000,000
Common Stock, Shares, Issued	45,600,002	45,600,002	45,600,002	45,600,002
Common Stock, Shares, Outstanding	42,976,340	42,976,340	43,636,984	43,636,984
Treasury Stock, Shares	2,623,662	2,623,662	1,963,018	1,963,018
Preferred Stock, Par or Stated Value Per Share		€ 0.02		€ 0.02
Preferred Stock, Shares Authorized	6,000,000	6,000,000	6,000,000	6,000,000
Preferred Stock, Shares Issued	0	0	0	0
Preferred Stock, Shares Outstanding	0	0	0	0