Stock-Based Compensation (Additional Information For RSU's Under The 2007 Plan) (Details) - 2007 and 2012 Incentive plan - Restricted Stock Units (RSUs) - shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Shares
Restricted Stock Units outstanding, beginning balance (in shares)	555,000	695,000	750,000
Granted (in shares)	136,000	154,000	187,000
Released (in shares)	(235,000)	(284,000)	(226,000)
Forfeited (in shares)	(10,000)	(10,000)	(16,000)
Restricted Stock Units outstanding, ending balance (in shares)	446,000	555,000	695,000
Expected to vest at end of year (in shares)	440,000	546,000	682,000