Consolidated Balance Sheets Balance Sheet Parenthetical $ in Thousands	Dec. 31, 2018 € / shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 € / shares	Dec. 31, 2017 USD ($) shares
Statement of Financial Position [Abstract]
Allowance for doubtful accounts | $		$ 2,650		$ 2,590
Preferred stock, par value per share | € / shares	€ 0.02		€ 0.02
Preferred stock, shares authorized		6,000,000		6,000,000
Preferred stock, shares issued		0		0
Preferred stock, shares outstanding		0		0
Common stock, par value per share | € / shares	€ 0.02		€ 0.02
Common stock, shares authorized		200,000,000		200,000,000
Common stock, shares, issued		44,796,252		44,796,252
Common shares, outstanding		44,316,845		44,184,205
Treasury stock, shares		479,407		612,047