General - Fair Value Measurements (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Assets
Restricted cash	$ 80,848	$ 133,597
Investments	336,807	326,165
Cash held in bank accounts by the Company, unrestricted	86,400	109,400
Cash held in bank accounts by the Company, restricted	34,000	50,800
Liabilities
Contingent consideration	93,404	92,426
Level 2 \| Term Loan
Liabilities
Fair value of debt	231,300
Fair value measured on recurring basis
Assets
Total assets held at fair value	383,828	414,982
Liabilities
Contingent consideration	93,404	92,426
Total liabilities held at fair value	93,404	92,426
Fair value measured on recurring basis \| Other than cash held in bank accounts by Company
Assets
Cash and cash equivalents	123	6,009
Restricted cash	46,898	82,808
Fair value measured on recurring basis \| U.S. Government and agency securities
Assets
Investments	5,127	5,514
Fair value measured on recurring basis \| Obligations of government-sponsored enterprises
Assets
Investments	52,545	50,525
Fair value measured on recurring basis \| Corporate debt securities
Assets
Investments	277,985	268,976
Fair value measured on recurring basis \| Certificates of deposit
Assets
Investments	1,150	1,150
Fair value measured on recurring basis \| Level 1
Assets
Total assets held at fair value	5,127	5,514
Fair value measured on recurring basis \| Level 1 \| U.S. Government and agency securities
Assets
Investments	5,127	5,514
Fair value measured on recurring basis \| Level 2
Assets
Total assets held at fair value	378,701	409,468
Fair value measured on recurring basis \| Level 2 \| Other than cash held in bank accounts by Company
Assets
Cash and cash equivalents	123	6,009
Restricted cash	46,898	82,808
Fair value measured on recurring basis \| Level 2 \| Obligations of government-sponsored enterprises
Assets
Investments	52,545	50,525
Fair value measured on recurring basis \| Level 2 \| Corporate debt securities
Assets
Investments	277,985	268,976
Fair value measured on recurring basis \| Level 2 \| Certificates of deposit
Assets
Investments	1,150	1,150
Fair value measured on recurring basis \| Level 3
Liabilities
Contingent consideration	93,404	92,426
Total liabilities held at fair value	$ 93,404	$ 92,426

Fair value of contingent consideration in a business combination as of the balance sheet date.

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Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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

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Amount 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. Excludes cash and cash equivalents within disposal group and discontinued operation.

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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.

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Fair value of financial and nonfinancial obligations.

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The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

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The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against short-term borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. For a classified balance sheet represents the current portion only (the noncurrent portion has a separate concept); there is a separate and distinct element for unclassified presentations.

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