Earnings Per Common Share (Tables)

12 Months Ended

Dec. 31, 2016

Earnings Per Share [Abstract]

Schedule of computation of basic and diluted earnings per common share

The following table sets forth the computation of basic and diluted earnings per common share:

Year ended December 31 (In thousands, except share data)	2016		2015		2014
Numerator:
Net income available to common shareholders	$	86,135	$	81,012	$	83,957
Denominator:
Weighted-average common shares outstanding	15,332,553		15,364,281		15,394,971
Effect of dilutive performance-based restricted stock units	72,607		40,459		18,861
Weighted-average common shares outstanding adjusted for the effect of dilutive performance-based restricted stock units	15,405,160		15,404,740		15,413,832
Earnings per common share:
Basic earnings per common share	$	5.62	$	5.27	$	5.45
Diluted earnings per common share	$	5.59	$	5.26	$	5.45