Amount of cost for defined contribution plan.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 70
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942

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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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- Definition

Amount of discretionary contributions made by an employer to a defined contribution plan.

+ References

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- Definition

Percentage employer matches of the employee's percentage contribution matched.

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- Definition

Description of defined contribution pension and other postretirement plans. Includes, but is not limited to, plan utilized, employee group covered, and employer matching contributions.

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Share-Based Compensation and Benefit Plans (Profit Sharing and Savings Plan) (Narrative) (Details) - Profit sharing and savings plan [Member] - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Share-Based Compensation and Benefit Plans
Profit sharing and savings plan, description			The Company sponsors a contributory profit sharing and savings plan (the “401(k) Plan”) that covers substantially all employees who are at least 21 years of age and have completed one year of service. The Company makes matching contributions equal to 100% of the first 2% of each employee’s wages that are contributed and 25% of the next 4% of each employee’s wages that are contributed.
Profit sharing and savings plan, employer discretionary contribution	$ 0.0	$ 0.0	$ 0.0	$ 0.0
Profit sharing and savings plan, cost recognized	$ 5.8	$ 5.5	$ 11.3	$ 10.5
Employee's first 2% of contributed wages [Member]
Share-Based Compensation and Benefit Plans
Profit sharing and savings plan, Company match			100.00%
Employee's next 4% of contributed wages [Member]
Share-Based Compensation and Benefit Plans
Profit sharing and savings plan, Company match			25.00%