XML 117 R101.htm IDEA: XBRL DOCUMENT v3.3.1.900
Share-Based Arrangements (Employee Stock Purchase Plan) (Details) - ESPP Stock [Member] - $ / shares
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award      
Market price after discount, purchase date 85.00%    
Number of shares authorized 1,500,000    
Employee stock issued (in shares) 79,294 76,805 85,702
Number of shares available for purchase 309,338    
Minimum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award      
Employee stock issued (in dollars per share) $ 31.64 $ 32.48 $ 28.34
Maximum [Member]      
Share-based Compensation Arrangement by Share-based Payment Award      
Employee stock issued (in dollars per share) $ 36.46 $ 36.42 $ 32.43