Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Current Assets:
Receivables, allowance for doubtful accounts	$ 1,101	$ 718
Property and Equipment, accumulated depreciation	352,293	338,206
Capitalized software, accumulated amortization	418,675	395,171
Intangible assets, accumulated amortization	$ 6,932	$ 5,090
Stockholders' Equity:
Common stock, par value (in USD per share)	$ 0.01	$ 0.01
Common stock, shares authorized	750,000,000	750,000,000
Common stock, shares issued	150,955,000	153,634,000
Common stock, shares outstanding	150,955,000	153,634,000

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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