XML 48 R37.htm IDEA: XBRL DOCUMENT v3.21.1
Equity Plans - Narrative (Details) - USD ($)
$ / shares in Units, $ in Thousands
3 Months Ended
Mar. 31, 2021
Mar. 31, 2020
Restricted stock and deferred restricted stock    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unrecognized compensation costs $ 7,203  
Recognition period for unrecognized compensation cost 2 years 2 months 12 days  
Restricted Stock Units (RSUs)    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of equity instruments granted (in shares) 33,701 28,367
Service-based restricted stock vesting period 1 year 3 years
Grant date fair value of equity instruments granted (usd per share) $ 64.22 $ 65.89
Performance Shares    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of equity instruments granted (in shares) 29,459 24,581
Grant date fair value of equity instruments granted (usd per share) $ 66.35 $ 73.85
Performance Shares | Minimum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Target vesting percentage 0.00%  
Performance Shares | Maximum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Target vesting percentage 150.00%  
Market-based RSU | Minimum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Target vesting percentage 0.00%  
Market-based RSU | Maximum    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Target vesting percentage 200.00%  
Incentive Plan | Restricted stock and deferred restricted stock    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Shares issuable upon exercise of Incentive Plan awards (in shares) 187,170  
Remaining shares available for issuance under the Incentive Plan (in shares) 688,365  
CTWS Plan | Restricted stock and deferred restricted stock    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Shares issuable upon exercise of Incentive Plan awards (in shares) 55,761  
Employee Stock Purchase Plan (ESPP)    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Unrecognized compensation costs $ 123  
Purchase price of common stock under ESPP (percent) 85.00%  
Maximum percentage of base compensation employees can designate for stock purchases under ESPP (percent) 10.00%  
Plan expense $ 88 $ 86
Employee Stock Purchase Plan (ESPP) | Common Stock    
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]    
Number of shares authorized for issuance under the plan (in shares) 400,000