Supplemental Cash Flow Information (Supplemental Cash Flow Information) (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2018	Mar. 31, 2017
Supplemental Cash Flow Information [Abstract]
Interest Paid, Net	$ 1,014	$ 1,151
Income Taxes Paid, Net	(90)	39
Change In Receivable For Securities Related To Investment Disposals That Settled After Balance Sheet Date	4,017	1,793
Change In Payable For Securities Related To Investment Purchases Settled After Balance Sheet Date	$ 3,360	$ (5,179)

Change in payable for securities related to investment purchases that settled after the statement date.

No definition available.

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- Definition

Change in receivable for securities related to investment disposals settled after the balance sheet date.

+ References

No definition available.

+ Details

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- References

No definition available.

+ Details

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- Definition

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4297-108586

+ Details

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- Definition

Amount of cash paid, after deduction of cash paid for capitalized interest, for interest. Includes, but is not limited to, payment to settle zero-coupon bond for accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount.

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+ Details

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