Summary of Changes in Goodwill (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2017 USD ($)
Goodwill [Line Items]
Balance at beginning of year	$ 108,128
Effect of foreign exchange rate changes	6,131
Balance at end of year	210,988
Laser Quantum
Goodwill [Line Items]
Goodwill acquired	31,168
Thing Magic
Goodwill [Line Items]
Goodwill acquired	9,929
World of Medicine GmbH
Goodwill [Line Items]
Goodwill acquired	$ 55,632