Consolidated Balance Sheets Parenthetical $ in Thousands	Jun. 30, 2021 USD ($) shares	Jun. 30, 2021 € / shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2020 € / shares
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts | $	$ 3,809		$ 4,068
Accumulated Depreciation | $	301,485		293,978
Accumulated amortization | $	$ 17,195		$ 16,833
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	46,454,264		44,796,252
Common shares, outstanding	46,325,530		44,572,801
Treasury stock, shares	128,734		223,451