Quarterly report pursuant to Section 13 or 15(d)

Senior Credit Facility (Details)

Senior Credit Facility (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Jun. 30, 2011
Oct. 10, 2007
Senior Credit Facility [Abstract]    
Senior credit facility amount   $ 100,000
Senior credit facility term (in years)   5
Additional borrowing capacity 50,000  
Base reference rate of credit facilities LIBOR  
Basis spread on variable rate minimum (in hundredths) 0.60%  
Basis spread on variable rate maximum (in hundredths) 0.90%  
Interest rate spread above LIBOR as of reporting period (in hundredths) 0.80%  
Outstanding under the senior credit facility 50,000  
Utilized for outstanding letters of credit 11,784  
Available borrowing capacity $ 38,216