Investments (Schedule of Amortized Cost, Unrealized Gains And Losses, And Market Value of Investment Securities) (Details) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Schedule of Available-for-sale Securities [Line Items]
Cash & Cash Equivalents	$ 374,688,291	$ 309,591,724
Cost	82,710,461	77,055,612
Unrealized Gains	26,605,035	29,998,513
Unrealized Losses	(347,917)	(48,603)
Investments	108,967,579	107,005,522
Investments and Cash	483,655,870	416,597,246
Long-Term Investments [Member] | Common Stocks
Schedule of Available-for-sale Securities [Line Items]
Cost	24,232,617	22,799,035
Unrealized Gains	10,024,316	10,532,007
Unrealized Losses	(125,840)	(48,603)
Investments	34,131,093	33,282,439
Long-Term Investments [Member] | Mutual Funds – Equity
Schedule of Available-for-sale Securities [Line Items]
Cost	58,477,844	54,256,577
Unrealized Gains	16,580,719	19,466,506
Unrealized Losses	(222,077)	0
Investments	74,836,486	73,723,083
Fair Value, Inputs, Level 1 [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash & Cash Equivalents	374,688,291	309,591,724
Investments and Cash	483,655,870	416,597,246
Fair Value, Inputs, Level 1 [Member] | Long-Term Investments [Member] | Common Stocks
Schedule of Available-for-sale Securities [Line Items]
Investments	34,131,093	33,282,439
Fair Value, Inputs, Level 1 [Member] | Long-Term Investments [Member] | Mutual Funds – Equity
Schedule of Available-for-sale Securities [Line Items]
Investments	74,836,486	73,723,083
Fair Value, Inputs, Level 2 [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash & Cash Equivalents		0
Investments and Cash	0	0
Fair Value, Inputs, Level 2 [Member] | Long-Term Investments [Member] | Common Stocks
Schedule of Available-for-sale Securities [Line Items]
Investments	0	0
Fair Value, Inputs, Level 2 [Member] | Long-Term Investments [Member] | Mutual Funds – Equity
Schedule of Available-for-sale Securities [Line Items]
Investments	0	0
Fair Value, Inputs, Level 3 [Member]
Schedule of Available-for-sale Securities [Line Items]
Cash & Cash Equivalents	0	0
Investments and Cash	0	0
Fair Value, Inputs, Level 3 [Member] | Long-Term Investments [Member] | Common Stocks
Schedule of Available-for-sale Securities [Line Items]
Investments	0	0
Fair Value, Inputs, Level 3 [Member] | Long-Term Investments [Member] | Mutual Funds – Equity
Schedule of Available-for-sale Securities [Line Items]
Investments	$ 0	$ 0