Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net income/(loss)	$ 18,568	$ (45,213)
Adjustments to reconcile net income/(loss) to net cash provided by operating activities:
Deferred income taxes	7,908	577
Provision for uncollectible revenue	(1,406)	2,359
Depreciation and amortization	57,638	55,306
Other post-employment benefits	(56,678)	(13,157)
Qualified pension	2,036	3,911
Stock-based compensation	2,666	2,857
Other non-cash items	1,102	1,024
Changes in assets and liabilities arising from operations:
Accounts receivable	(1,841)	(923)
Prepaid and other assets	(79)	4,557
Accounts payable and accrued liabilities	2,961	(1,948)
Accrued interest payable	(6,563)	(6,563)
Other assets and liabilities, net	(2,281)	(1,996)
Total adjustments	5,463	46,004
Net cash provided by operating activities	24,031	791
Cash flows from investing activities:
Net capital additions	(25,880)	(26,430)
Distributions from investments and proceeds from the sale of property and equipment	175	195
Net cash used in investing activities	(25,705)	(26,235)
Cash flows from financing activities:
Repayments of long-term debt	(1,600)	(1,600)
Proceeds from exercise of stock options	2	4
Repayment of capital lease obligations	(224)	(231)
Net cash used in financing activities	(1,822)	(1,827)
Net change	(3,496)	(27,271)
Cash, beginning of period	26,560	37,587
Cash, end of period	23,064	10,316
Supplemental disclosure of cash flow information:
Capital additions included in accounts payable	8,691	8,498
Acquisition of property and equipment by capital lease	$ 355	$ 270