Earnings Per Common Share (Computation Of Basic And Diluted Net Earnings Per Share) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Net income	$ 15,516	$ 14,639
Basic earnings per common share, Income (Numerator)	15,516	14,639
Basic earnings per common share, Shares (Denominator)	71,469	70,321
Basic earnings per common share (dollars per share)	$ 0.22	$ 0.21
Effect of dilutive securities, Options, Shares (Denominator)	690	751
Effect of dilutive securities, Options, (dollars per share)	$ 0.00	$ 0.00
Diluted earnings per common share, Income (Numerator)	$ 15,516	$ 14,639
Diluted earnings per common share, Shares (Denominator)	72,159	71,072
Diluted earnings per common share (dollars per share)	$ 0.22	$ 0.21
Options outstanding to purchase common stock excluded from computation of diluted earnings per common share (shares)	1,014	993
Antidilutive securities excluded from earnings per share, average exercise price (dollars per share)	$ 29.22	$ 25.87