Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Current assets:
Cash and cash equivalents	$ 468,936	$ 476,492
Accounts receivable:
Trade, net of allowance for uncollectible accounts of $7,775 and $4,735, respectively	114,285	104,724
Unbilled revenue	31,870	28,542
Costs in excess of billing	774	2,034
Current deferred tax assets	36,059	31,180
Other current assets	44,500	51,301
Total current assets	696,424	694,273
Property and equipment	2,515,691	2,241,444
Less accumulated depreciation	(581,368)	(506,060)
Property and equipment, net	1,934,323	1,735,384
Other assets:
Equity investments	143,481	149,623
Goodwill	61,648	62,146
Other assets, net	72,124	59,272
Total assets	2,908,000	2,700,698
Current liabilities:
Accounts payable	75,781	83,403
Accrued liabilities	78,718	104,923
Income tax payable	0	9,143
Current maturities of long-term debt	71,640	28,144
Total current liabilities	226,139	225,613
Long-term debt	704,568	523,228
Deferred tax liabilities	257,596	260,275
Other non-current liabilities	46,412	38,108
Total liabilities	$ 1,234,715	$ 1,047,224
Commitments and contingencies
Shareholders’ equity:
Common stock, no par, 240,000 shares authorized, 106,116 and 105,586 shares issued, respectively	$ 944,718	$ 934,447
Retained earnings	808,166	781,279
Accumulated other comprehensive loss	(79,599)	(62,252)
Total shareholders’ equity	1,673,285	1,653,474
Total liabilities and shareholders’ equity	$ 2,908,000	$ 2,700,698