NET INCOME PER COMMON SHARE (Tables)
 9 Months Ended
Sep. 30, 2016
NET INCOME PER COMMON SHARE [Abstract]  
Components of Computation of Basic and Diluted Net Income per Common Share
Components of the computation of basic and diluted net income per common share were as follows for the indicated periods (dollars in thousands, except per share amounts):

  
Quarter Ended
September 30
  
Nine Months Ended
September 30
 
  
2016
  
2015
  
2016
  
2015
 
Basic net income per common share
            
Numerator for basic net income per common share:
            
Net income
 
$
16,440
  
$
21,067
  
$
65,423
  
$
79,968
 
Preferred stock dividends
  
(3,846
)
  
(3,809
)
  
(11,515
)
  
(11,339
)
Earnings participation of unvested equity awards
  
(40
)
  
(28
)
  
(123
)
  
(95
)
  
$
12,554
  
$
17,230
  
$
53,785
  
$
68,534
 
Denominator for basic net income per common share:
                
Average number of shares of common stock outstanding
  
95,978
   
95,814
   
95,946
   
95,814
 
Average unvested stock awards outstanding
  
(300
)
  
(284
)
  
(299
)
  
(314
)
   
95,678
   
95,530
   
95,647
   
95,500
 
  
$
0.13
  
$
0.18
  
$
0.56
  
$
0.72
 
Diluted net income per common share
                
Numerator for diluted net income per common share:
                
Numerator for basic net income per common share
 
$
12,554
  
$
17,230
  
$
53,785
  
$
68,534
 
                 
Denominator for diluted net income per common share:
                
Denominator for basic net income per common share
  
95,678
   
95,530
   
95,647
   
95,500
 
Net effect of dilutive equity awards
  
188
   
191
   
152
   
195
 
   
95,866
   
95,721
   
95,799
   
95,695
 
  
$
0.13
  
$
0.18
  
$
0.56
  
$
0.72