• Filing Date: 2018-03-07
  • Form Type: 10-K
  • Description: Annual report
v3.8.0.1
Stockholders' Equity (Share Repurchase Agreement) - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Apr. 03, 2017
Mar. 03, 2017
Class of Stock [Line Items]          
Repurchase and retirement of common stock, value $ 21,318 $ 464 $ 792    
Share Repurchase Plan [Member]          
Class of Stock [Line Items]          
Repurchase and retirement of common stock, value 15,154 $ 20,026 $ 1,610    
Institutional Investors [Member] | Share Repurchase Plan [Member]          
Class of Stock [Line Items]          
Repurchase and retirement of common stock, value $ 20,345        
Repurchase and retirement of common stock, shares 413,600        
Common stock repurchased and retired, price per share $ 49.19        
4.25% Convertible Senior Notes [Member]          
Class of Stock [Line Items]          
Debt instrument stated interest rate 4.25%     4.25% 4.25%