Quarterly report pursuant to Section 13 or 15(d)

Share-Based Payments - Employee Activity Performance Shares (Details)

v3.4.0.3
Share-Based Payments - Employee Activity Performance Shares (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 3 Months Ended
Mar. 31, 2016
Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Share-based compensation expense $ 1,952 $ 1,786
Key Employee Performance Share Based Plan [Member]    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Period of Share Price Performance Comparison to Peer Group 3 years  
Minimum percentage of peer group by which Company share price must outperform before incremental performance shares are issued 30.00%  
Percentage of Peer Group By Which Company Share Price Must Outperform Before Maximum Incremental Shares Are Issued 90.00%  
Expected Stock Price Volatility Rate 22.30% 23.50%
Weighted Average Risk Free Interest Rate 0.80% 1.00%
Outstanding and non-vested, beginning of period (in shares) 77  
Grants in Period 29  
Additional Shares Awarded Based on Performance, Shares Issued in Period 7  
Shares Vested in Period (33)  
Outstanding and non-vested, end of period (in shares) 80  
Outstanding and non-vested, weighted-average grant date fair value, beginning of period $ 52  
Grants in Period, Weighted Average Grant Date Fair Value 49  
Stock Issued During Period, Weighted Average Grant Date Fair Value 40  
Vested in Period, Weighed-average grant date fair value 40  
Outstanding and non-vested, weighted-average grant date fair value, end of period $ 55  
Outstanding and non-vested, aggregate grant date fair value $ 4,373  
Share-based compensation expense 351 $ 302
Tax benefit related to share-based expense 131 116
Unrecognized share-based compensation, net of estimated forfeitures $ 2,805 $ 2,733
Weighted average period over which unrecognized compensation will be recognized (years) 2 years 2 months 11 days