Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Current assets:
Cash and cash equivalents	$ 492,190	$ 494,192
Accounts receivable:
Trade, net of allowance for uncollectible accounts of $316 and $350, respectively	59,888	76,287
Unbilled revenue and other	16,216	20,465
Current deferred tax assets	14,211	53,573
Income tax receivable	21,311	0
Other current assets	41,465	39,518
Total current assets	645,281	684,035
Property and equipment	2,565,180	2,544,857
Less accumulated depreciation	(983,218)	(941,848)
Property and equipment, net	1,581,962	1,603,009
Other assets:
Equity investments	0	26,200
Goodwill	45,107	45,107
Other assets, net	42,018	41,608
Total assets	2,314,368	2,399,959
Current liabilities:
Accounts payable	48,013	65,370
Accrued liabilities	71,009	71,641
Income tax payable	0	2,261
Current maturities of long-term debt	71,786	71,640
Total current liabilities	190,808	210,912
Long-term debt	638,985	677,695
Deferred tax liabilities	166,557	180,974
Other non-current liabilities	52,829	51,415
Total liabilities	1,049,179	1,120,996
Commitments and contingencies
Shareholders’ equity:
Common stock, no par, 240,000 shares authorized, 112,627 and 106,289 shares issued, respectively	986,239	945,565
Retained earnings	365,805	404,299
Accumulated other comprehensive loss	(86,855)	(70,901)
Total shareholders’ equity	1,265,189	1,278,963
Total liabilities and shareholders’ equity	$ 2,314,368	$ 2,399,959