Investment in Securities, Investment in Securities (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Available for sale securities:
Available for sale Securities, Cost	$ 79,139	$ 38,178	$ 38,650
Available for sale Securities, Fair Value	108,495	79,846	77,288
Investment in Securities, Fair Value	126,917	259,537	254,630
Investment in Securities [Member]
Available for sale securities:
Investment in Securities, Cost	95,222	207,464	206,787
Investment in Securities, Fair Value	126,917	259,537	254,630
Investment in Securities [Member] \| Trading Securities [Member]
Trading securities:
Trading Securities, Cost	81,034	193,146	191,878
Trading Securities, Fair Value	91,648	219,227	216,861
Investment in Securities [Member] \| Trading Securities [Member] \| Government obligations [Member]
Trading securities:
Trading Securities, Cost	0	18,994	20,995
Trading Securities, Fair Value	0	18,996	20,999
Investment in Securities [Member] \| Trading Securities [Member] \| Common Stock [Member]
Trading securities:
Trading Securities, Cost	78,025	170,977	167,714
Trading Securities, Fair Value	87,745	195,029	190,939
Investment in Securities [Member] \| Trading Securities [Member] \| Mutual Funds [Member]
Trading securities:
Trading Securities, Cost	2,504	2,432	2,416
Trading Securities, Fair Value	3,180	3,498	3,373
Investment in Securities [Member] \| Trading Securities [Member] \| Other Investments [Member]
Trading securities:
Trading Securities, Cost	505	743	753
Trading Securities, Fair Value	723	1,704	1,550
Investment in Securities [Member] \| Available-for-sale Securities [Member]
Available for sale securities:
Available for sale Securities, Cost	14,188	14,318	14,909
Available for sale Securities, Fair Value	35,269	40,310	37,769
Investment in Securities [Member] \| Available-for-sale Securities [Member] \| Common Stock [Member]
Available for sale securities:
Available for sale Securities, Cost	13,561	13,637	14,228
Available for sale Securities, Fair Value	34,095	38,942	36,380
Investment in Securities [Member] \| Available-for-sale Securities [Member] \| Mutual Funds [Member]
Available for sale securities:
Available for sale Securities, Cost	627	681	681
Available for sale Securities, Fair Value	$ 1,174	$ 1,368	$ 1,389

This item represents a parenthetical disclosure for the cost of securities.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 25

-Paragraph 1

-Subparagraph (b)

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-Publisher FASB

-Name Accounting Standards Codification

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-Publisher FASB

-Name Accounting Standards Codification

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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)

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Total debt and equity financial instruments including: (1) securities held-to-maturity, (2) trading securities, and (3) securities 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 5

-Subparagraph (d)

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-Name Accounting Standards Codification

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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27161-111563

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

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Amount of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=49167202&loc=d3e26626-111562

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-Publisher FASB

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-Publisher FASB

-Name Accounting Standards Codification

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-Section 45

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-URI http://asc.fasb.org/extlink&oid=49167202&loc=d3e26610-111562

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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Cost of investments in debt and equity securities and other forms of securities that provide ownership interests classified as trading.

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