CONDENSED CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDER'S EQUITY (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Capital Stock Expense	Retained Earnings	Accumulated Other Comprehensive Loss
Balances at Dec. 31, 2016	$ 1,559,035	$ 1,296,539	$ (6,357)	$ 273,408	$ (4,555)
Increase (Decrease) in Stockholder's Equity [Roll Forward]
Net Income	163,694			163,694
Other Comprehensive Income, Net of Tax	545				545
Dividend Declared to Parent	(35,000)			(35,000)
Balances at Sep. 30, 2017	1,688,274	1,296,539	(6,357)	402,102	(4,010)
Balances at Dec. 31, 2017	1,664,032	1,296,539	(6,357)	380,076	(6,226)
Increase (Decrease) in Stockholder's Equity [Roll Forward]
Net Income	176,373			176,373
Other Comprehensive Income, Net of Tax	646				646
Dividend Declared to Parent	(40,000)			(40,000)
Adoption of ASU, Cumulative Effect Adjustment				878	(878)
Balances at Sep. 30, 2018	$ 1,801,051	$ 1,296,539	$ (6,357)	$ 517,327	$ (6,458)

Tax Cuts and Jobs Act of 2017, Reclassification from AOCI to Retained Earnings

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Amount of paid and unpaid common stock dividends declared with the form of settlement in cash, stock and payment-in-kind (PIK).

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A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

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Amount, after deduction of tax, noncontrolling interests, dividends on preferred stock and participating securities; of income (loss) available to common shareholders.

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Amount after tax and reclassification adjustments of other comprehensive income (loss).

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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