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Deferred Compensation Plan (Details) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Deferred Compensation Plans [Line Items]      
Imputed interest rate credited to the Deferred Compensation Plan participant's account as a percentage to Moody's Composite Average of Yields on Corporate Bonds 130.00%    
Interest expense $ 26,692 $ 22,532 $ 22,049
Deferred compensation liability 13,700 11,700  
Accrued liabilities compensation and benefits [Member]      
Deferred Compensation Plans [Line Items]      
Deferred compensation liability 500 500  
Other compensation and benefits [Member]      
Deferred Compensation Plans [Line Items]      
Deferred compensation liability 13,200 11,200  
Deferred compensation arrangement with individual [Member]      
Deferred Compensation Plans [Line Items]      
Interest expense $ 700 $ 600 $ 600