STATEMENT OF CHANGES IN EQUITY - 9 months ended Sep. 30, 2018 - USD ($) $ in Thousands	Total	Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Shares issued, beginning balance at Dec. 31, 2017	52,598,005	52,598,005
Equity, beginning balance at Dec. 31, 2017	$ 1,960,209	$ 526	$ 1,737,551	$ 246,121	$ (18,496)	$ (5,493)
Net income	127,530	0	0	127,530	0	0
Other comprehensive income	326	$ 0	0	0		326
Common stock issued, shares		0
Common stock issued, value	991	$ 0	(12,862)	0	13,853	0
Common stock dividends - $0.92 per share	$ (72,432)	$ 0	672	(73,104)	0	0
Shares issued, ending balance at Sep. 30, 2018	52,598,005	52,598,005
Equity, ending balance at Sep. 30, 2018	$ 2,016,624	$ 526	$ 1,725,361	$ 300,547	$ (4,643)	$ (5,167)