XML 28 R53.htm IDEA: XBRL DOCUMENT v2.4.0.8
Retirement Plans - Additional Information (Details) (USD $)
12 Months Ended
May 31, 2013
May 31, 2012
May 31, 2011
Defined Benefit Plan Disclosure [Line Items]      
Reduction in accrued liability $ 2,200,000    
Cumulative post-retirement plan adjustment, net of tax 18,400,000 24,500,000  
Cumulative post-retirment plan adjustment, tax 3,500,000 1,400,000  
Defined Benefit Plan
     
Defined Benefit Plan Disclosure [Line Items]      
Approximate number of employees and retirees of subsidiary 600    
Pension and other benefit obligations 77,100,000 88,500,000  
Pension and other benefit obligations, current 3,800,000 3,700,000  
Riverside Defined Benefit Plans
     
Defined Benefit Plan Disclosure [Line Items]      
Approximate number of employees and retirees of subsidiary 600    
Contribution expected to be made during the next year 2,300,000    
Accumulated benefit obligation 62,400,000 64,000,000  
Assumed long-term rate of return 7.30%    
Assumed health care cost trend rate for the next year 9.00%    
Year for ultimate health care cost trend rate 2022    
Effect of one percentage point increase on benefit obligation 303,000    
Effect of one percentage point decrease on benefit obligation 308,000    
Effect of one percentage point increase on plan expense 25,000    
Effect of one percentage point decrease on plan expense 25,000    
Riverside Defined Benefit Plans | Forecast
     
Defined Benefit Plan Disclosure [Line Items]      
Ultimate health care cost trend rate 5.00%    
Riverside Defined Benefit Plans | Equity securities
     
Defined Benefit Plan Disclosure [Line Items]      
Target asset allocations 60.00%    
Riverside Defined Benefit Plans | Fixed income securities
     
Defined Benefit Plan Disclosure [Line Items]      
Target asset allocations 40.00%    
Riverside Defined Benefit Plans | Pension Plans
     
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan, expected future benefit payments, 2014 3,300,000    
Defined benefit plan, expected future benefit payments, 2015 3,500,000    
Defined benefit plan, expected future benefit payments, 2016 3,600,000    
Defined benefit plan, expected future benefit payments, 2017 3,700,000    
Defined benefit plan, expected future benefit payments, 2018 3,700,000    
Defined benefit plan, expected future benefit payments thereafter 19,700,000    
Assumed long-term rate of return 7.30% 7.60% 8.25%
Assumed discount rate 4.50% 4.35%  
Net periodic benefit cost 1,274,000 2,191,000 2,781,000
Riverside Defined Benefit Plans | Other Benefits
     
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan, expected future benefit payments, 2014 200,000    
Defined benefit plan, expected future benefit payments, 2015 200,000    
Defined benefit plan, expected future benefit payments, 2016 300,000    
Defined benefit plan, expected future benefit payments, 2017 300,000    
Defined benefit plan, expected future benefit payments, 2018 300,000    
Defined benefit plan, expected future benefit payments thereafter 2,100,000    
Defined Contribution Pension Plan
     
Defined Benefit Plan Disclosure [Line Items]      
Net periodic benefit cost 500,000 1,200,000 2,800,000
Financial Security Defined Benefit Plans
     
Defined Benefit Plan Disclosure [Line Items]      
Defined benefit plan, expected future benefit payments, 2014 3,600,000    
Defined benefit plan, expected future benefit payments, 2015 4,000,000    
Defined benefit plan, expected future benefit payments, 2016 4,400,000    
Defined benefit plan, expected future benefit payments, 2017 4,400,000    
Defined benefit plan, expected future benefit payments, 2018 4,500,000    
Defined benefit plan, expected future benefit payments thereafter 21,000,000    
Assumed discount rate 4.35% 4.30%  
Net periodic benefit cost $ 4,696,000 $ 9,030,000 $ 6,871,000