STATEMENT OF CHANGES IN EQUITY (USD $) In Thousands, except Share data	Total	Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Retained earnings, beginning balance at Dec. 31, 2014	$ 39,894			$ 39,894
Accumulated Other Comprehensive Income (Loss), beginning balance at Dec. 31, 2014	(5,174)		1,758,796		(5,174)
Total equity, beginning balance at Dec. 31, 2014	1,794,037
Paid-in Capital, beginning balance at Dec. 31, 2014	1,758,796
Common Stock Issued, beginning balance at Dec. 31, 2014	521	521
Common Stock Issued (in shares), beginning balance at Dec. 31, 2014	52,083,859	52,083,859
Cash payment to ONEOK upon separation	0
Net income	60,381	0	0	60,381	0
Other comprehensive income	(140)	0	0	0	(140)
Common stock issued, shares		506,253
Common stock issued, value	880	5	875	0	0
Common stock dividends - $0.30 per share	(15,773)	0	(263)	(16,036)	0
Retained earnings, ending balance at Mar. 31, 2015	84,239			84,239
Accumulated Other Comprehensive Income (Loss), ending balance at Mar. 31, 2015	(5,034)		1,759,934		(5,034)
Total equity, ending balance at Mar. 31, 2015	1,839,665
Paid-in Capital, ending balance at Mar. 31, 2015	1,759,934
Common Stock Issued, ending balance at Mar. 31, 2015	$ 526	$ 526
Common Stock Issued (in share), ending balance at Mar. 31, 2015	52,590,112	52,590,112