Net Income Per Share (Computation Of Weighted Average Shares Outstanding Basic And Diluted) (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Common shares	23,293,173	25,354,677	23,491,872	25,446,821
Vested restricted stock units	680,926	570,950	659,208	546,568
Basic number of weighted average shares outstanding	23,974,099	25,925,627	24,151,080	25,993,389
Dilutive effect of stock options	37,814	48,202	38,536	52,862
Dilutive effect of restricted stock and restricted stock units	5,360	6,043	30,787	36,861
Dilutive number of weighted average shares outstanding	24,017,273	25,979,872	24,220,403	26,083,112
Restricted Stock [Member]
Shares outstanding excluded from calculation of diluted net income per share				8,422
Stock Options, Restricted Stock Or Restricted Stock Units [Member]
Shares outstanding excluded from calculation of diluted net income per share	0	0	0