Condensed Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 390,435	$ 356,647
Accounts receivable:
Trade, net of allowance for uncollectible accounts of $2,752 and $1,778, respectively	83,555	101,825
Unbilled revenue and other	40,312	10,328
Current deferred tax assets	0	16,594
Other current assets	40,206	37,388
Total current assets	554,508	522,782
Property and equipment	2,562,835	2,450,890
Less accumulated depreciation	(851,432)	(799,280)
Property and equipment, net	1,711,403	1,651,610
Other assets, net	95,651	72,549
Total assets	2,361,562	2,246,941
Current liabilities:
Accounts payable	86,601	60,210
Accrued liabilities	60,119	58,614
Current maturities of long-term debt	107,205	67,571
Total current liabilities	253,925	186,395
Long-term debt	408,250	558,396
Deferred tax liabilities	154,826	167,351
Other non-current liabilities	46,926	52,985
Total liabilities	863,927	965,127
Commitments and contingencies
Shareholders’ equity:
Common stock, no par, 240,000 shares authorized, 147,670 and 120,630 shares issued, respectively	1,279,162	1,055,934
Retained earnings	300,036	322,854
Accumulated other comprehensive loss	(81,563)	(96,974)
Total shareholders’ equity	1,497,635	1,281,814
Total liabilities and shareholders’ equity	$ 2,361,562	$ 2,246,941