Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 266,592	$ 356,647
Accounts receivable:
Trade, net of allowance for uncollectible accounts of $2,752 and $1,778, respectively	113,336	101,825
Unbilled revenue and other	29,947	10,328
Current deferred tax assets	0	16,594
Other current assets	41,768	37,388
Total current assets	451,643	522,782
Property and equipment	2,695,772	2,450,890
Less accumulated depreciation	(889,783)	(799,280)
Property and equipment, net	1,805,989	1,651,610
Other assets, net	105,205	72,549
Total assets	2,362,837	2,246,941
Current liabilities:
Accounts payable	81,299	60,210
Accrued liabilities	71,680	58,614
Income tax payable	2,799	0
Current maturities of long-term debt	109,861	67,571
Total current liabilities	265,639	186,395
Long-term debt	385,766	558,396
Deferred tax liabilities	103,349	167,351
Other non-current liabilities	40,690	52,985
Total liabilities	795,444	965,127
Shareholders’ equity:
Common stock, no par, 240,000 shares authorized, 147,740 and 120,630 shares issued, respectively	1,284,274	1,055,934
Retained earnings	352,906	322,854
Accumulated other comprehensive loss	(69,787)	(96,974)
Total shareholders’ equity	1,567,393	1,281,814
Total liabilities and shareholders’ equity	$ 2,362,837	$ 2,246,941