Accounting Policies - Additional Information (Details)
12 Months Ended
Dec. 31, 2016
USD ($)
Facilities
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Accounting Policies [Abstract]      
Research and development expense $ 17,123,000 $ 18,677,000 $ 23,149,000
Advertising expense $ 13,593,000 $ 9,203,000 $ 13,463,000
Number of subsidiaries | Facilities 2    
Unremitted earnings of foreign subsidiaries $ 32,700,000