Basis Of Presentation (Details) (USD $)	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Identifiable intangible assets minimum useful life (years)										1 year 6 months
Advertising Expense									$ 55,400,000	$ 48,100,000	$ 45,400,000
Accumulated Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Net of Tax	(1,821,000)				(1,899,000)				(1,821,000)	(1,899,000)	(800,000)
Revenues									520,801,000	371,396,000	330,159,000
Net earnings	20,754,000	27,806,000	36,040,000	22,922,000	30,203,000	31,650,000	31,188,000	28,539,000	107,522,000	121,580,000	114,766,000
Basic earnings per share	$ 0.45	$ 0.60	$ 0.78	$ 0.50	$ 0.66	$ 0.69	$ 0.68	$ 0.61	$ 2.31	$ 2.63	$ 2.46
Diluted earnings per share	$ 0.44	$ 0.59	$ 0.77	$ 0.49	$ 0.65	$ 0.69	$ 0.67	$ 0.60	$ 2.28	$ 2.61	$ 2.43
Foreign Currency Transaction Gain (Loss), Realized									400,000	(100,000)	0
Remaining Service Obligations To eFax Customers [Member]
Revenues											10,300,000
Net earnings											$ 7,600,000
Basic earnings per share											$ 0.17
Diluted earnings per share											$ 0.16
Minimum [Member]
Identifiable intangible assets minimum useful life (years)									1 year
Property, Plant and Equipment, Useful Life									1 year
Maximum [Member]
Identifiable intangible assets minimum useful life (years)									20 years
Property, Plant and Equipment, Useful Life									5 years