XML 135 R108.htm IDEA: XBRL DOCUMENT v3.10.0.1
Derivative Instruments And Hedging Activities - Narrative (Detail)
 12 Months Ended
Dec. 31, 2018
USD ($)
derivative
Swap
swap
Dec. 31, 2017
USD ($)
derivative
Swap
Derivative Instruments, Gain (Loss) [Line Items]    
Reclassification from AOCI to interest expense $ 200,000  
Period for hedging exposure to the variability in future cash flows for forecasted transactions 30 months  
Assets needed for immediate settlement of derivatives in a net liability position $ 2,600,000  
Minimum collateral with counterparties 700,000  
Interest rate swaps    
Derivative Instruments, Gain (Loss) [Line Items]    
Derivative notional amount $ 500,000,000  
Interest Rate Swap    
Derivative Instruments, Gain (Loss) [Line Items]    
Number of interest rate swaps | swap 3  
Not Designated as Hedging Instrument | Minimum    
Derivative Instruments, Gain (Loss) [Line Items]    
Derivative expiration period 30 days  
Not Designated as Hedging Instrument | Maximum    
Derivative Instruments, Gain (Loss) [Line Items]    
Derivative expiration period 60 days  
Not Designated as Hedging Instrument | Interest Rate Swap    
Derivative Instruments, Gain (Loss) [Line Items]    
Number of interest rate swaps | Swap 98 76
Derivative notional amount $ 1,030,100,000.0 $ 800,500,000.0
Not Designated as Hedging Instrument | Residential mortgage loan commitments    
Derivative Instruments, Gain (Loss) [Line Items]    
Derivative notional amount 3,600,000.0 2,700,000.0
Not Designated as Hedging Instrument | Credit contracts    
Derivative Instruments, Gain (Loss) [Line Items]    
Derivative notional amount $ 94,900,000.0 $ 80,500,000.0
Cash Flow Hedging | Designated as Hedging Instrument    
Derivative Instruments, Gain (Loss) [Line Items]    
Number of interest rate swaps | derivative   9
Derivative notional amount   $ 550,000,000
Cash Flow Hedging | Designated as Hedging Instrument | Interest Rate Swap    
Derivative Instruments, Gain (Loss) [Line Items]    
Number of interest rate swaps | derivative 6 9
Derivative notional amount $ 750,000,000 $ 550,000,000
Other Non-interest Income | Not Designated as Hedging Instrument | Interest rate swaps    
Derivative Instruments, Gain (Loss) [Line Items]    
Gain on cash flow hedge ineffectiveness $ 4,800,000