Share-Based Compensation and Benefit Plans (Stock Option Activity) (Details) - Stock option [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-Based Compensation and Benefit Plans
Compensation expense for share-based compensation	$ 16,521	$ 15,561	$ 15,404
Income tax benefit from compensation expense for share-based compensation	4,093	5,934	5,753
Total intrinsic value of options exercised	156,327	135,533	157,115
Cash received from the exercise of stock options	$ 61,403	$ 33,229	$ 47,394
Weighted-average grant date fair value of options awarded	$ 76.57	$ 62.79	$ 63.42
Weighted-average remaining contractual life of options currently exercisable	4 years 5 months 7 days	3 years 9 months 21 days	3 years 10 months 14 days
Employee stock option [Member]
Share-Based Compensation and Benefit Plans
Weighted-average remaining contractual life of options currently exercisable	4 years 5 months 7 days

Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees.

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The total recognized tax benefit related to compensation cost for equity-based payment arrangements recognized in income during the period.

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- Definition

Amount of cash inflow from issuance of shares under share-based compensation arrangement. Issuance includes, but is not limited to, exercise of stock options and similar instruments.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares.

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- Definition

The weighted average grant-date fair value of options granted during the reporting period as calculated by applying the disclosed option pricing methodology.

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Weighted average remaining contractual term for vested portions of options outstanding and currently exercisable or convertible, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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