Annual report pursuant to Section 13 and 15(d)

Leases - Additional Information (Detail)

v3.19.3.a.u2
Leases - Additional Information (Detail)
 12 Months Ended
Dec. 31, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Jan. 01, 2019
USD ($)
lease
Lessee, Lease, Description [Line Items]        
Number of leases | lease       45
Right-of-use assets $ 36,500,000      
Total lease liabilities - Operating leases 37,159,000      
Net rental expenses $ 7,900,000 $ 7,400,000 $ 7,000,000.0  
Weighted average remaining lease term 8 years 6 months 25 days      
Weighted average discount rate (percent) 3.24%      
Net lease expense $ 7,900,000      
Operating lease costs 8,000,000.0      
Sublease income 132,000      
Cash paid for amounts included in the measurement of Company's operating lease liabilities $ 7,200,000      
ASU 2016-02        
Lessee, Lease, Description [Line Items]        
Right-of-use assets       $ 40,900,000
Total lease liabilities - Operating leases       $ 40,900,000
Minimum        
Lessee, Lease, Description [Line Items]        
Initial lease terms 2 years      
Lease renewal term 2 years      
Maximum        
Lessee, Lease, Description [Line Items]        
Initial lease terms 25 years      
Lease renewal term 12 years