Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current Assets:
Receivables, allowance for doubtful accounts	$ 605	$ 695
Property and Equipment, accumulated depreciation	323,992	309,955
Capitalized software, accumulated amortization	372,249	350,045
Intangible assets, accumulated amortization	$ 3,248	$ 1,552
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	156,800,000	157,069,000
Common stock, shares outstanding	156,800,000	157,069,000

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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