Annual report pursuant to Section 13 and 15(d)

Acquisition - Additional Information (Detail)

v3.6.0.2
Acquisition - Additional Information (Detail)
 12 Months Ended
Oct. 27, 2016
USD ($)
Aug. 31, 2014
USD ($)
$ / shares
Dec. 31, 2016
USD ($)
Branches
Dec. 31, 2015
USD ($)
Dec. 31, 2014
USD ($)
Business Acquisition [Line Items]          
Goodwill     $ 11,031,000 $ 0  
Bargain purchase gain     0 0 $ 14,577,000
Merger and integration expense     $ 312,000 1,971,000 6,646,000
Banc of California Leases Acquisition [Member]          
Business Acquisition [Line Items]          
Cash consideration paid $ 240,800,000        
Other tangible and intangible assets acquired 12,600,000        
Goodwill 11,000,000        
Central Bancorp, Inc [Member]          
Business Acquisition [Line Items]          
Intangible asset amortization period   10 years      
Common stock, price per share after acquisition (in usd per share) | $ / shares   $ 17.64      
Consideration paid   $ 50,000,000      
Consideration paid for redemption of preferred stock   28,675,000      
Total assets acquired   1,267,921,000      
Total liabilities assumed   1,174,669,000      
Total identifiable net assets   93,252,000      
Loans   297,272,000      
Total deposits   1,098,997,000      
Number of branch locations | Branches     23    
Bargain purchase gain   14,577,000      
Merger and integration expense     $ 2,000,000 6,600,000  
Core deposit intangible   2,213,000      
Amortization expense of core deposit intangible     326,000 379,000 132,000
Certificates of deposit   11,300,000      
Amortization of certificates of deposit     2,700,000 5,600,000 2,300,000
Discount on subordinated debentures   $ 8,300,000      
Amortization of subordinated debentures     $ 275,000 $ 176,000 $ 71,000
Lease Intangible Asset [Member] | Banc of California Leases Acquisition [Member]          
Business Acquisition [Line Items]          
Estimated fair value of acquired intangibles 228,200,000        
Third Party Originators Intangible [Member]          
Business Acquisition [Line Items]          
Intangible asset amortization period     7 years    
Third Party Originators Intangible [Member] | Banc of California Leases Acquisition [Member]          
Business Acquisition [Line Items]          
Estimated fair value of acquired intangibles $ 483,000        
Intangible asset amortization period 7 years