Pension and Other Postretirement Plans (Amounts Recognized in Financial Statements and Other Comprehensive Income) (Details) - USD ($)
Dec. 31, 2016
Dec. 31, 2015
Defined Benefit Pension Plans    
Amount recognized in the Company's consolidated financial statements    
Assets $ 0 $ 0
Liabilities (6,274,000) (7,355,000)
Net amount recognized (6,274,000) (7,355,000)
Amount recognized in accumulated other comprehensive income    
Net loss 9,443,000 11,039,000
Prior service cost 0 0
Net amount recognized 9,443,000 11,039,000
Chairman and President Non-Qualified Defined Benefit Plans    
Amount recognized in the Company's consolidated financial statements    
Assets 0 0
Liabilities (26,232,000) (22,735,000)
Net amount recognized (26,232,000) (22,735,000)
Amount recognized in accumulated other comprehensive income    
Net loss 11,865,000 9,885,000
Prior service cost 641,000 700,000
Net amount recognized 12,506,000 10,585,000
Defined Benefit Postretirement Healthcare Plans    
Amount recognized in the Company's consolidated financial statements    
Assets 0 0
Liabilities (3,366,000) (3,307,000)
Net amount recognized (3,366,000) (3,307,000)
Amount recognized in accumulated other comprehensive income    
Net loss 436,000 480,000
Prior service cost 258,000 361,000
Net amount recognized $ 694,000 $ 841,000