CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Statement of Cash Flows [Abstract]
Net Cash Provided by Operating Activities	$ 34,936	$ 49,232
Cash Flows from Investing Activities:
Capital Expenditures	(54,307)	(60,254)
Net Proceeds from Sale of Restricted Investments in Margin Account	4,829	7,444
Purchase of Available-for-Sale Securities	(6,059)	0
Investment in Long-Term Receivables	(4,658)	(2,053)
Proceeds from Long-Term Receivables	1,808	1,981
Purchase of Company Owned Life Insurance	(356)	(230)
Investment in Affiliate	(717)	0
Advances on Notes Receivable - Affiliate	(1,265)	(342)
Repayment of Notes Receivable - Affiliate	275	3,228
Net Cash Used in Investing Activities	(60,450)	(50,226)
Cash Flows from Financing Activities:
Net Borrowings from (Repayments of) Short-Term Credit Facilities	26,700	(29,600)
Proceeds from Issuance of Long-Term Debt	0	30,000
Payments for Issuance of Long-Term Debt	0	(210)
Proceeds from Sale of Common Stock	1,857	5,157
Net Cash Provided by Financing Activities	28,557	5,347
Net Increase in Cash and Cash Equivalents	3,043	4,353
Cash and Cash Equivalents at Beginning of Period	4,171	3,818
Cash and Cash Equivalents at End of Period	$ 7,214	$ 8,171