Significant Accounting Policies Investments (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Schedule of Available-for-sale Securities [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (320,000)	$ (532,000)
Cost	64,796,000	76,606,000
Gross Gains	12,000
Gross Losses	(2,000)	(257,000)
Fair Value	64,806,000	76,349,000
Short-term investments in a continuous unrealized loss position, twelve months or longer	0
Corporate Debt Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	36,947,000	26,575,000
Gross Gains	10,000
Gross Losses		(139,000)
Fair Value	36,957,000	26,436,000
Commercial Paper [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	13,991,000	18,464,000
Gross Gains	2,000
Gross Losses		(2,000)
Fair Value	13,993,000	18,462,000
Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	13,858,000	12,520,000
Gross Gains
Gross Losses	(2,000)	(116,000)
Fair Value	13,856,000	12,404,000
Certificates of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost		19,047,000
Gross Gains
Fair Value		$ 19,047,000