Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 494,192	$ 476,492
Accounts receivable:
Trade, net of allowance for uncollectible accounts of $350 and $4,735, respectively	76,287	104,724
Unbilled revenue	20,434	28,542
Costs in excess of billing	31	2,034
Current deferred tax assets	53,573	31,180
Other current assets	39,518	51,301
Total current assets	684,035	694,273
Property and equipment	2,544,857	2,241,444
Less accumulated depreciation	(941,848)	(506,060)
Property and equipment, net	1,603,009	1,735,384
Other assets:
Equity investments	26,200	149,623
Goodwill	45,107	62,146
Other assets, net	53,601	59,272
Total assets	2,411,952	2,700,698
Current liabilities:
Accounts payable	65,370	83,403
Accrued liabilities	71,641	104,923
Income tax payable	2,261	9,143
Current maturities of long-term debt	71,640	28,144
Total current liabilities	210,912	225,613
Long-term debt	689,688	523,228
Deferred tax liabilities	180,974	260,275
Other non-current liabilities	51,415	38,108
Total liabilities	$ 1,132,989	$ 1,047,224
Commitments and contingencies
Shareholders’ equity:
Common stock, no par, 240,000 shares authorized, 106,289 and 105,586 shares issued, respectively	$ 945,565	$ 934,447
Retained earnings	404,299	781,279
Accumulated other comprehensive loss	(70,901)	(62,252)
Total shareholders’ equity	1,278,963	1,653,474
Total liabilities and shareholders’ equity	$ 2,411,952	$ 2,700,698