Statement of Member's Equity Statement of Member's Equity - USD ($) $ in Thousands	Total	MEMBER'S CAPITAL	RETAINED EARINGS	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
Balance at beginning of period at Dec. 31, 2015		$ 1,073,892	$ 296,668	$ 28
Net income (loss)	$ 180,455		180,455
Cash distributions to parent	(174,000)		(174,000)
Reclassification of unrecognized gain into earnings	(28)			(28)
Balance at end of period at Dec. 31, 2016	1,377,015	1,073,892	303,123	0
Net income (loss)	(27,834)		(27,834)
Cash distributions to parent	(186,000)		(186,000)
Reclassification of unrecognized gain into earnings	0			0
Balance at end of period at Dec. 31, 2017	1,163,181	$ 1,073,892	89,289	0
Net income (loss)	131,461		131,461
Cash distributions to parent	(174,000)		(174,000)
Reclassification of unrecognized gain into earnings	0			0
Balance at end of period at Dec. 31, 2018	$ 1,120,642		$ 46,750	$ 0