Condensed Consolidated Statements of Cash Flows - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Cash flows from operating activities:
Net loss	$ (91,659)	$ (86,803)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation, depletion, amortization and accretion	114,281	136,672
Deferred income taxes	(29,747)	(55,371)
Stock based compensation expense	10,691	10,783
Other reconciling items, net	(1,430)	(63)
Changes in operating assets and liabilities:
Accounts receivable	(32,441)	71,602
Inventory and other current assets	(8,826)	(6,529)
Accounts payable	11,731	(14,979)
Accrued expenses	17,673	(5,307)
Income taxes	(20,496)	8,987
Other, net	(12,592)	3,543
Net cash provided by (used in) operating activities	(42,815)	62,535
Cash flows from investing activities:
Payments for capital expenditures	(21,188)	(38,015)
Decrease in cash held in escrow	30,600
Other	4,090	1,880
Net cash provided by (used in) investing activities	13,502	(36,135)
Cash flows from financing activities:
Cash dividends		(12,111)
Proceeds from revolving line of credit		325,000
Principal payments of long-term debt		(329,106)
Tax withholdings for vested restricted stock units	(8,220)	(3,435)
Other	(486)	(7,295)
Net cash used in financing activities	(8,706)	(26,947)
Effect of exchange rate changes on cash	2,194	(4,232)
Net decrease in cash and cash equivalents	(35,825)	(4,779)
Cash and cash equivalents at beginning of period	187,591	564,017
Cash and cash equivalents at end of period	$ 151,766	$ 559,238