XML 67 R57.htm IDEA: XBRL DOCUMENT v3.10.0.1
Share Repurchase Program - Additional Information (Detail) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
May 31, 2018
Class of Stock Disclosures [Abstract]          
Additional common stock shares, authorized for repurchase         700,000
Purchase of treasury stock, shares 216,156 0 527,212 0  
Purchase of treasury stock, per share value $ 29.18   $ 31.76    
Purchase of treasury stock $ 6,308   $ 16,742    
Common stock shares, available for repurchase 483,844   483,844