NET INCOME PER COMMON SHARE (Tables)

12 Months Ended

Dec. 31, 2016

Earnings Per 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): 

	Year ended December 31
	2016			2015			2014
Basic net income per common share
Numerator for basic net income per common share:
Net income	$	82,873		$	108,325		$	140,820
Preferred stock dividends		(15,372	)		(15,160	)		(13,781	)
Earnings participation of unvested equity awards		(140	)		(123	)		(95	)
	$	67,361		$	93,042		$	126,944
Denominator for basic net income per common share:
Average number of shares of common stock outstanding		95,957			95,817			95,789
Average unvested stock awards outstanding		(301	)		(308	)		(398	)
		95,656			95,509			95,391
	$	0.70		$	0.97		$	1.33
Diluted net income per common share
Numerator for diluted net income per common share:
Numerator for basic net income per common share	$	67,361		$	93,042		$	126,944
Denominator for diluted net income per common share:
Denominator for basic net income per common share		95,656			95,509			95,391
Net effect of dilutive equity awards		163			192			238
		95,819			95,701			95,629
	$	0.70		$	0.97		$	1.33