Fair Value Measurements (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair Value, Level 1
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and Cash Equivalents, Fair Value Disclosure	$ 137,266	$ 37,499
Available-for-sale Securities, Fair Value Disclosure	201,521	91,077
Investments, Fair Value Disclosure	338,787	128,576
Other Liabilities, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	0	0
Fair Value, Level 2
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Available-for-sale Securities, Fair Value Disclosure	552	552
Investments, Fair Value Disclosure	552	552
Other Liabilities, Fair Value Disclosure	0	0
Liabilities, Fair Value Disclosure	0	0
Fair Value, Level 3
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Available-for-sale Securities, Fair Value Disclosure	0	0
Investments, Fair Value Disclosure	0	0
Other Liabilities, Fair Value Disclosure	17,638	27,710
Liabilities, Fair Value Disclosure	17,638	27,710
Fair Value, Total
Fair Value, Balance Sheet Grouping, Financial Statement Captions
Cash and Cash Equivalents, Fair Value Disclosure	137,266	37,499
Available-for-sale Securities, Fair Value Disclosure	202,073	91,629
Investments, Fair Value Disclosure	339,339	129,128
Other Liabilities, Fair Value Disclosure	17,638	27,710
Liabilities, Fair Value Disclosure	$ 17,638	$ 27,710

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

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)

-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

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-Subparagraph (aa)

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Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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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

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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 Available-for-Sale Securities

-URI http://asc.fasb.org/extlink&oid=6505594

Reference 2: 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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

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-URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558

Reference 4: 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

Reference 5: http://www.xbrl.org/2003/role/presentationRef

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Fair value of financial and nonfinancial obligations.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

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Fair value portion of other liabilities.

+ References

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