CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (UNAUDITED) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Statement of Cash Flows [Abstract]
Net Cash Provided by Operating Activities	$ 62,509	$ 56,213
Cash Flows from Investing Activities:
Capital Expenditures	(88,305)	(96,891)
Net (Purchase of) Proceeds from Sale of Restricted Investments in Margin Account	(13,840)	7,775
Purchase of Restricted Investments with Escrowed Loan Proceeds	(40)	0
Investment in Long-Term Receivables	(3,256)	(2,871)
Proceeds from Long-Term Receivables	3,433	3,781
Purchase of Company Owned Life Insurance	(3,785)	(3,525)
Investment in Affiliate	(2,492)	(28,979)
Advances on Notes Receivable - Affiliate	(6,157)	(58,178)
Repayment of Notes Receivable - Affiliate	94,360	4,681
Other	0	(584)
Net Cash Used in Investing Activities	(20,082)	(174,791)
Cash Flows from Financing Activities:
Net (Repayments of) Borrowings from Short-Term Credit Facilities	(43,200)	1,900
Proceeds from Issuance of Long-Term Debt	0	150,000
Principal Repayments of Long-Term Debt	0	(35,000)
Payments for Issuance of Long-Term Debt	(5)	(583)
Premium for Early Retirement of Debt	0	(700)
Dividends on Common Stock	(14,102)	(12,200)
Proceeds from Sale of Common Stock	12,502	9,256
Net Cash (Used in) Provided by Financing Activities	(44,805)	112,673
Net Decrease in Cash and Cash Equivalents	(2,378)	(5,905)
Cash and Cash Equivalents at Beginning of Period	4,638	7,538
Cash and Cash Equivalents at End of Period	$ 2,260	$ 1,633