Net Income Per Common Share (Tables)

6 Months Ended

Jun. 30, 2012

Net Income Per Common Share [Abstract]

Basic and diluted net income per common share

	Income (Numerator)		Shares (Denominator)		Per Share Amount
	(Dollars in thousands, except per share data)
Three Months Ended June 30, 2012
Basic
Income available to common stockholders	$	11,729		15,155,525	$	0.77
Effect of stock options		—		271,271
Diluted
Income available to common stockholders plus assumed exercises of stock options	$	11,729		15,426,796	$	0.76
Three Months Ended June 30, 2011
Basic
Income available to common stockholders	$	10,115		15,364,738	$	0.66
Effect of stock options		—		287,215
Diluted
Income available to common stockholders plus assumed exercises of stock options	$	10,115		15,651,953	$	0.65
Six Months Ended June 30, 2012
Basic
Income available to common stockholders	$	25,734		15,145,066	$	1.70
Effect of stock options		—		276,608
Diluted
Income available to common stockholders plus assumed exercises of stock options	$	25,734		15,421,674	$	1.67
Six Months Ended June 30, 2011
Basic
Income available to common stockholders	$	21,470		15,362,764	$	1.40
Effect of stock options		—		295,723
Diluted
Income available to common stockholders plus assumed exercises of stock options	$	21,470		15,658,487	$	1.37

Average exercise prices of options excluded from the computation of diluted net income per common share

	Shares		Average Exercise  Price
Three Months Ended June 30, 2012		607,200	$	38.70
Three Months Ended June 30, 2011		537,008	$	38.94
Six Months Ended June 30, 2012		607,200	$	38.70
Six Months Ended June 30, 2011		503,857	$	38.80