Earnings Per Common Share (Tables)

9 Months Ended

Sep. 30, 2011

Earnings Per Common Share [Abstract]

Basic And Diluted Earnings Per Common Share

	Three Months Ended September 30,				Nine Months Ended September 30,
	2011		2010		2011		2010
Distributed earnings allocated to common stock	$	28,123	$	27,251	$	83,695	$	80,248
Undistributed earnings allocated to common stock		26,238		27,529		77,868		74,849
Net earnings allocated to common stock	$	54,361	$	54,780	$	161,563	$	155,097
Weighted-average shares outstanding for basic earnings per common share		61,137,054		60,523,658		61,083,390		60,289,006
Dilutive effect of stock compensation		102,092		141,045		199,013		178,699
Weighted-average shares outstanding for diluted earnings per common share		61,239,146		60,664,703		61,282,403		60,467,705