Investments (Schedule Of Amortized Cost, Unrealized Gains And Losses, And Market Value Of Investment Securities) (Details) (USD $)	Sep. 30, 2012	Dec. 31, 2011
Schedule of Available-for-sale Securities [Line Items]
Cost	$ 141,761,786	$ 172,957,560
Unrealized Gains	25,570,357	18,597,832
Unrealized Losses	(721,967)	(2,578,990)
Investments	166,610,176	188,976,402
Short-Term Investments [Member] | Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	21,295,669	35,016,980
Unrealized Gains	3,346	7,090
Unrealized Losses	(150)	(40)
Investments	21,298,865	35,024,030
Short-Term Investments [Member] | U.S. Treasury Notes [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost		25,025,600
Unrealized Gains		18,400
Investments		25,044,000
Short-Term Investments [Member] | Corporate Bond Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost		648,879
Unrealized Gains		325
Investments		649,204
Short-Term Investments [Member] | Other [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	223,434	91,003
Investments	223,434	91,003
Long-Term Investments [Member] | Government Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	5,000,217
Unrealized Gains	1,483
Investments	5,001,700
Long-Term Investments [Member] | Corporate Bond Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	5,789,019
Unrealized Gains	29,090
Unrealized Losses	(4,388)
Investments	5,813,721
Long-Term Investments [Member] | Certificate Of Deposit [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	510,881	505,390
Investments	510,881	505,390
Long-Term Investments [Member] | Common Stocks [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	40,253,871	42,344,526
Unrealized Gains	14,267,950	12,274,640
Unrealized Losses	(522,793)	(1,064,863)
Investments	53,999,028	53,554,303
Long-Term Investments [Member] | Mutual Funds - Equity [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	68,100,189	68,986,676
Unrealized Gains	11,251,594	6,277,183
Unrealized Losses	(194,636)	(1,514,087)
Investments	79,157,147	73,749,772
Long-Term Investments [Member] | Other - Equity [Member]
Schedule of Available-for-sale Securities [Line Items]
Cost	588,506	338,506
Unrealized Gains	16,894	20,194
Investments	$ 605,400	$ 358,700