Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended
	Dec. 31, 2017 USD ($) segment plan	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Summary Of Significant Accounting Policies [Line Items]
Number of reportable segments | segment	3
Standard product warranty period	1 year
Deposits with foreign banks	$ 98,800,000	$ 87,300,000
Sales demonstration inventory turnover period (up to)	3 years
Refurbished sales demonstration inventory turnover period	12 months
Service inventory turnover period	12 months
Service inventory not for sale, useful life	3 years
Reserve percentage of FIFO obsolete and excess inventory	100.00%
Depreciation expense	$ 12,300,000	10,900,000	$ 9,200,000
Indefinite-lived intangible assets	$ 0	0
Intangible assets weighted-average amortization period	8 years
Number of compensation plans | plan	2
Performance Shares
Summary Of Significant Accounting Policies [Line Items]
Vesting period, years	3 years
Long Lived Assets
Summary Of Significant Accounting Policies [Line Items]
Assets impairment charges	$ 0	0	$ 0
Minimum
Summary Of Significant Accounting Policies [Line Items]
Account receivable period due	30 days
Other intangible assets, useful life	3 years
Minimum | Product technology and patents
Summary Of Significant Accounting Policies [Line Items]
Other intangible assets, useful life	7 years
Maximum
Summary Of Significant Accounting Policies [Line Items]
Account receivable period due	90 days
Other intangible assets, useful life	20 years
Maximum | Product technology and patents
Summary Of Significant Accounting Policies [Line Items]
Other intangible assets, useful life	20 years
Accounting Standards Update 2015-17
Summary Of Significant Accounting Policies [Line Items]
Reclassification of deferred tax assets		$ 7,600,000