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, 2013	Mar. 31, 2012
Earnings Per Share [Abstract]
Net income	$ 14,954	$ 8,578
Basic earnings per common share, Income (Numerator)	14,954	8,578
Basic earnings per common share, Shares (Denominator)	68,463	67,084
Basic earnings per common share (dollars per share)	$ 0.22	$ 0.13
Effect of dilutive securities, Options, Shares	898	1,001
Effect of dilutive securities, Options, (dollars per share)	$ 0.00	$ 0.00
Diluted earnings per common share, Income (Numerator)	$ 14,954	$ 8,578
Diluted earnings per common share, Shares (Denominator)	69,361	68,085
Diluted earnings per common share (dollars per share)	$ 0.22	$ 0.13
Options outstanding to purchase common stock excluded from computation of diluted earnings per common share	544	574
Antidilutive securities excluded from earnings per share, average exercise price	$ 23.50	$ 17.50