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Investments (Schedule of Amortized Cost, Unrealized Gains And Losses, And Market Value of Investment Securities) (Details) - USD ($) | Jun. 30, 2015 | Dec. 31, 2014
--- | --- | ---
Schedule of Available-for-sale Securities [Line Items] |  |
Cash & Cash Equivalents | $ 569,896,553 | $ 497,429,804
Cost | 101,584,848 | 97,923,092
Unrealized Gains | 14,464,744 | 17,855,921
Unrealized Losses | (1,308,492) | (1,135,425)
Market Value | 114,741,100 | 114,643,588
Investments and Cash | 684,637,653 | 612,073,392
Short-term Investments [Member] | Other Debt Obligations [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cost | 454 | 1,021
Unrealized Gains | 0 | 0
Unrealized Losses | 0 | 0
Market Value | 454 | 1,021
Long-Term Investments [Member] | Common Stock |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cost | 18,690,052 | 17,069,742
Unrealized Gains | 5,639,978 | 7,933,717
Unrealized Losses | (644,310) | (355,008)
Market Value | 23,685,720 | 24,648,451
Long-Term Investments [Member] | Mutual Funds – Equity |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cost | 82,894,342 | 80,852,329
Unrealized Gains | 8,824,766 | 9,922,204
Unrealized Losses | (664,182) | (780,417)
Market Value | 91,054,926 | 89,994,116
Fair Value, Inputs, Level 1 [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cash & Cash Equivalents | 569,896,553 | 497,429,804
Investments and Cash | 684,637,653 | 612,073,392
Fair Value, Inputs, Level 1 [Member] | Short-term Investments [Member] | Other Debt Obligations [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Market Value | 454 | 1,021
Fair Value, Inputs, Level 1 [Member] | Long-Term Investments [Member] | Common Stock |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Market Value | 23,685,720 | 24,648,451
Fair Value, Inputs, Level 1 [Member] | Long-Term Investments [Member] | Mutual Funds – Equity |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Market Value | 91,054,926 | 89,994,116
Fair Value, Inputs, Level 2 [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Cash & Cash Equivalents | 0 | 0
Investments and Cash | 0 | 0
Fair Value, Inputs, Level 2 [Member] | Short-term Investments [Member] | Other Debt Obligations [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Market Value | 0 | 0
Fair Value, Inputs, Level 2 [Member] | Long-Term Investments [Member] | Common Stock |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Market Value | 0 | 0
Fair Value, Inputs, Level 2 [Member] | Long-Term Investments [Member] | Mutual Funds – Equity |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Market Value | 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] | Short-term Investments [Member] | Other Debt Obligations [Member] |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Market Value | 0 | 0
Fair Value, Inputs, Level 3 [Member] | Long-Term Investments [Member] | Common Stock |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Market Value | 0 | 0
Fair Value, Inputs, Level 3 [Member] | Long-Term Investments [Member] | Mutual Funds – Equity |  |
Schedule of Available-for-sale Securities [Line Items] |  |
Market Value | $ 0 | $ 0

X
- Definition Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 + Details
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- Definition Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563 + Details
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- Definition This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.2) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
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- Definition Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash -URI http://asc.fasb.org/extlink&oid=6506951 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Cash Equivalents -URI http://asc.fasb.org/extlink&oid=6507016 + Details
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- Definition Sum of investments and unrestricted cash as of the balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.1,2) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
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- Definition Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Trading Securities -URI http://asc.fasb.org/extlink&oid=6526789 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 35 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=27723805&loc=d3e24584-111560 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=51813488&loc=d3e22054-111558 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Available-for-Sale Securities -URI http://asc.fasb.org/extlink&oid=6505594 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 1 -Subparagraph a, f, g -Article 7 + Details
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