Net Income Attributable To IPG Photonics Corporation Per Share (Computation Diluted Net Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Net income attributable to IPG Photonics Corporation	$ 75,559	$ 100,517	$ 121,617	$ 106,334	$ 52,956	$ 115,597	$ 104,116	$ 74,945	$ 404,027	$ 347,614	$ 260,752
Net income attributable to common stockholders									$ 404,027	$ 347,614	$ 260,752
Weighted average shares (in shares)									53,522	53,495	53,068
Dilutive effect of common stock equivalents (in shares)									1,204	1,204	729
Diluted weighted average common shares (in shares)									54,726	54,699	53,797
Basic net income attributable to IPG Phontonics Corporation per share (in dollars per share)									$ 7.55	$ 6.50	$ 4.91
Basic net income attributable to common stockholders (in dollars per share)	$ 1.42	$ 1.88	$ 2.27	$ 1.98	$ 0.99	$ 2.16	$ 1.95	$ 1.40	7.55	6.50	4.91
Diluted net income attributable to IPG Photonics Corporation per share (in dollars per share)									7.38	6.36	4.85
Diluted net income attributable to common stockholders (in dollars per share)	$ 1.40	$ 1.84	$ 2.21	$ 1.93	$ 0.96	$ 2.11	$ 1.91	$ 1.38	$ 7.38	$ 6.36	$ 4.85