CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDER'S EQUITY - USD ($) $ in Thousands	Total	Common Stock	Capital Stock Expense	Retained Earnings	Accumulated Other Comprehensive Loss
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Adoption of ASU, Cumulative Effect Adjustment	$ 9,653			$ 9,653
Balances at December 31 at Dec. 31, 2015	1,474,935	$ 1,296,539	$ (6,357)	189,317	$ (4,564)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	124,438			124,438
Other Comprehensive Income (Loss), Net of Tax	9				9
Dividends Declared to Parent	(50,000)			(50,000)
Balances at December 31 at Dec. 31, 2016	1,559,035	1,296,539	(6,357)	273,408	(4,555)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	176,668			176,668
Other Comprehensive Income (Loss), Net of Tax	(1,671)				(1,671)
Dividends Declared to Parent	(70,000)			(70,000)
Balances at December 31 at Dec. 31, 2017	1,664,032	1,296,539	(6,357)	380,076	(6,226)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income	188,323			188,323
Other Comprehensive Income (Loss), Net of Tax	2,390				2,390
Dividends Declared to Parent	(85,000)			(85,000)
Contribution from Parent	50,000	50,000
Adoption of ASU, Cumulative Effect Adjustment				878	(878)
Balances at December 31 at Dec. 31, 2018	$ 1,819,745	$ 1,346,539	$ (6,357)	$ 484,277	$ (4,714)

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

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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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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