Stock-based Compensation (Schedule of Information Relating to ESPP) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense for ESPP	$ 2,936,000	$ 2,160,000	$ 1,917,000
Total amount of cash received from the purchase of stock through ESPP	$ 673,000	$ 661,000	$ 521,000
Employee Stock Purchase Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average fair value per share of shares purchased	$ 11.26	$ 13.01	$ 5.66
Total compensation expense for ESPP	$ 324,250	$ 461,980	$ 409,079
Total amount of cash received from the purchase of stock through ESPP	672,899	660,621	521,308
Total intrinsic value of ESPP stock purchased at December 31st	$ 233,381	$ 75,892	$ 863,120