Debt Obligations (Schedule of Long Term Obligations) (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020
Debt Instrument [Line Items]
Total long term obligations	$ 1,369,194	$ 1,479,077
Unsecured Debt	697,046	493,376
Line of Credit Facility, Maximum Borrowing Capacity	800,000
Convertible Debt	229,300	222,391
Other Long-term Debt	10,848	11,141
Less: current portion	(625)	(13,746)
Total long term obligations, net	1,368,569	1,465,331
Unsubordinated term loan [Member]
Debt Instrument [Line Items]
Total long term obligations	0	612,169
Revolving credit facility [Member]
Debt Instrument [Line Items]
Total long term obligations	$ 432,000	$ 140,000

Including the current and noncurrent portions, carrying amount of debt identified as being convertible into another form of financial instrument (typically the entity's common stock) as of the balance sheet date, which originally required full repayment more than twelve months after issuance or greater than the normal operating cycle of the company.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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