Marketable Securities - Additional Information (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Schedule of Available-for-sale Securities [Line Items]
Fair market value of investment securities exceeds cost basis	$ 115,000		$ 115,000
Other-than-temporary impairments recorded for securities	0		0
Changes in unrealized gains on available for sale securities, taxes	(132,000)	99,000	(121,000)	(353,000)
Estimated taxes of change in value of available-for-sale securities			48,000
Gross unrealized holding gains			207,000
Gross unrealized holding losses			$ 92,000