Earnings Per Share (Computation Of Basic Earnings And Diluted Earnings Per Share Data) (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Earnings Per Share [Abstract]
Net income	$ 7,105	$ 5,624	$ 12,786	$ 11,352
Weighted-average basic common shares outstanding	30,171,000	32,005,000	30,175,000	31,912,000
Stock options	2,598,000	1,843,000	2,557,000	1,738,000
Denominator for diluted earnings per share - Adjusted weighted-average shares	32,769,000	33,848,000	32,732,000	33,650,000
Basic	$ 0.24	$ 0.18	$ 0.42	$ 0.36
Diluted	$ 0.22	$ 0.17	$ 0.39	$ 0.34
Antidilutive securities excluded from computation of earnings per share, amount	470,000	562,000	451,000	790,000