XML 61 R51.htm IDEA: XBRL DOCUMENT v3.8.0.1
Derivatives - Additional Information (Detail)
3 Months Ended
Mar. 31, 2018
USD ($)
Mar. 31, 2017
USD ($)
Dec. 31, 2017
USD ($)
Jun. 30, 2016
USD ($)
Derivative
Derivative [Line Items]        
Available for sale securities pledged for collateral $ 500,000   $ 500,000  
Interest Expense 7,909,000 $ 5,473,000    
Reclassification Out of Accumulated Other Comprehensive Income        
Derivative [Line Items]        
Interest Expense $ 364,000      
Cash Flow Hedging | Interest Rate Swaps        
Derivative [Line Items]        
Number of derivatives | Derivative       2
Notional amount       $ 30,000,000
Average interest rate       1.10%
Variable rate basis 3 month LIBOR      
Amount of ineffective hedges $ 0      
Cash Flow Hedging | Interest Rate Swaps | Interest Expense        
Derivative [Line Items]        
Amount of accumulated other comprehensive income reclassified into interest expense $ 43,000 $ 8,000