Annual report pursuant to Section 13 and 15(d)

Employee Retirement Benefits (Narrative) (Details)

v3.7.0.1
Employee Retirement Benefits (Narrative) (Details) - USD ($)
 3 Months Ended 12 Months Ended
Mar. 31, 2016
Dec. 31, 2015
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]          
Contributions to the plan     $ 554,000 $ 591,000 $ 528,000
Pension settlement costs       1,222,276  
Pension liability adjustments     $ (4,147,836)    
Maximum matching percentage by employer     6.00%    
Austin Taylor Pension Plan [Member]          
Defined Benefit Plan Disclosure [Line Items]          
Contributions to the plan $ 68,000     650,000  
Pension settlement costs $ 43,000 $ 1,222,000 $ 43,000 $ (1,720,000)