Equity Method Investments - Activity Related to Equity Method Investments (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Equity Method Investments
Balance at beginning of period			$ 103,517	$ 68,029
Contributions			24,176	20,798
Earnings (loss) on equity method investments	$ (1,727)	$ 1,648	208	4,581
Balance at end of period	$ 127,901	93,408	$ 127,901	93,408
Constitution
Schedule of Equity Method Investments [Line Items]
Ownership percentage	25.00%		25.00%
Equity Method Investments
Balance at beginning of period			$ 90,345	64,269
Contributions			8,325	13,500
Earnings (loss) on equity method investments			211	4,608
Balance at end of period	$ 98,881	82,377	98,881	82,377
Contributions to date	$ 87,900		$ 87,900
Meade
Schedule of Equity Method Investments [Line Items]
Ownership percentage	20.00%		20.00%
Equity Method Investments
Balance at beginning of period			$ 13,172	3,760
Contributions			15,851	7,298
Earnings (loss) on equity method investments			(3)	(27)
Balance at end of period	$ 29,020	$ 11,031	29,020	$ 11,031
Investment Commitment
Equity Method Investments
Expected future contributions	30,000		30,000
Investment Commitment \| Constitution
Equity Method Investments
Anticipated contributions	$ 240,000		$ 240,000

Equity Method Investment, Contributions to Date

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Equity Method Investments [Roll Forward]

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The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

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This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

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Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

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Amount of other commitments maturing in the remainder of the fiscal year following the latest fiscal year ended.

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- Definition

The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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