Consolidated Statements of Stockholders' Equity (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net Actuarial Loss, Tax	$ (8,429)	$ 19,914	$ 30,323
Unrealized Loss on Cash Flow Hedges, Tax	$ (37)	$ 0	$ 0
Retirement of Common Stock (in shares)	1,717,497	708,245	0
Shares repurchased	26,297	167,958
CCR Units
Shares repurchased	26,297	167,958

Amount of tax expense (benefit) for reclassification of gain (loss) from accumulated other comprehensive income (AOCI) for derivative instrument designated and qualifying as cash flow hedge included in assessment of hedge effectiveness.

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