Quarterly report pursuant to Section 13 or 15(d)

Derivative Financial Instruments (Classifications on Consolidated Balance Sheets) (Details)

v3.10.0.1
Derivative Financial Instruments (Classifications on Consolidated Balance Sheets) (Details) - Designated as Hedging Instrument [Member] - USD ($)
 6 Months Ended
Jun. 30, 2018
Dec. 31, 2017
Derivative [Line Items]    
Notional Amount $ 515,000,000  
Fair Value 8,928,000 $ 5,345,000
Interest Rate Swap One [Member]    
Derivative [Line Items]    
Notional Amount $ 150,000,000  
Company Fixed Pay Rate 1.30%  
Fair Value $ 150,000 326,000
Interest Rate Swap Two [Member]    
Derivative [Line Items]    
Notional Amount $ 175,000,000  
Company Fixed Pay Rate 1.03%  
Fair Value $ 6,930,000 5,207,000
Interest Rate Swap Three [Member]    
Derivative [Line Items]    
Notional Amount $ 40,000,000  
Company Fixed Pay Rate 2.47%  
Fair Value $ 180,000 0
Interest Rate Swap Four [Member]    
Derivative [Line Items]    
Notional Amount $ 150,000,000  
Company Fixed Pay Rate 2.20%  
Fair Value $ 1,668,000 $ (188,000)
London Interbank Offered Rate (LIBOR) [Member] | Interest Rate Swap One [Member]    
Derivative [Line Items]    
Bank Pay Rate 1 month  
London Interbank Offered Rate (LIBOR) [Member] | Interest Rate Swap Two [Member]    
Derivative [Line Items]    
Bank Pay Rate 1 month  
London Interbank Offered Rate (LIBOR) [Member] | Interest Rate Swap Three [Member]    
Derivative [Line Items]    
Bank Pay Rate 1 month  
London Interbank Offered Rate (LIBOR) [Member] | Interest Rate Swap Four [Member]    
Derivative [Line Items]    
Bank Pay Rate 1 month