PARENT COMPANY FINANCIAL INFORMATION (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
ASSETS        
Investment securities available-for-sale $ 1,034,180 $ 1,267,491    
Other assets 104,000 113,742    
TOTAL ASSETS 4,583,413 5,006,404    
LIABILITIES:        
Statutory Trust Debenture 25,370 25,352    
Total liabilities 3,968,267 4,372,531    
COMMITMENTS AND CONTINGENCIES          
STOCKHOLDERS' EQUITY        
Preferred Stock - $.01 par value; 100,000,000 shares authorized, none issued or outstanding as of December 31, 2013 and 2012          
Common Stock - $.01 par value; 300,000,000 shares authorized 82,298,707 and 82,279,507 issued and 77,123,026 and 79,297,478 shares outstanding as of December 31, 2013 and 2012, respectively 823 823    
Additional paid-in capital 356,963 354,082    
Unearned common stock held by employee savings and stock ownership plan (16,102) (17,901)    
Retained earnings (partially restricted) 342,025 329,447    
Accumulated other comprehensive loss (21,354) (7,027)    
Treasury Stock, at cost, 5,175,681 shares and 2,982,029 shares at December 31, 2013 and 2012, respectively (47,209) (25,551)    
Total stockholders' equity 615,146 633,873 629,380 615,547
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY 4,583,413 5,006,404    
Beneficial Mutual Bancorp, Inc.
        
ASSETS        
Cash on deposit at the Bank 3,818 539    
Interest-bearing deposit at the Bank 32,754 32,086    
Investment in the Bank 598,132 618,879    
Investment in Statutory Trust 774 774    
Investment securities available-for-sale 12 120    
Receivable from the Bank 1,707 4,186    
Other assets 3,598 2,796    
TOTAL ASSETS 640,795 659,380    
LIABILITIES:        
Accrued and other liabilities 258 135    
Accrued interest payable 21 20    
Statutory Trust Debenture 25,370 25,352    
Total liabilities 25,649 25,507    
COMMITMENTS AND CONTINGENCIES          
STOCKHOLDERS' EQUITY        
Preferred Stock - $.01 par value; 100,000,000 shares authorized, none issued or outstanding as of December 31, 2013 and 2012          
Common Stock - $.01 par value; 300,000,000 shares authorized 82,298,707 and 82,279,507 issued and 77,123,026 and 79,297,478 shares outstanding as of December 31, 2013 and 2012, respectively 823 823    
Additional paid-in capital 356,963 354,082    
Unearned common stock held by employee savings and stock ownership plan (16,102) (17,901)    
Retained earnings (partially restricted) 342,025 329,447    
Accumulated other comprehensive loss (21,354) (7,027)    
Treasury Stock, at cost, 5,175,681 shares and 2,982,029 shares at December 31, 2013 and 2012, respectively (47,209) (25,551)    
Total stockholders' equity 615,146 633,873    
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY $ 640,795 $ 659,380