Long-term Debt Covenants & Guarantees (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Acquisition amount that will trigger higher senior secured leverage ratio	$ 500
Debt Instrument, Covenant Compliance	the Company was in compliance with the covenants under the Credit Agreement
Credit Agreement [Member]
Stock Repurchase Program, Additional Allowable Amount Under Credit Agreement	$ 500
Maximum [Member] | Credit Agreement [Member]
Total coverage ratio after repurchase of stock	3.25
Senior secured leverage ratio through June 30, 2019	4.25
Senior secured leverage ratio after June 30, 2019	4.00
Debt Instrument, Covenant, Senior Secured Leverage Ratio, After Exceeding Acquisition Limit	4.50
Maximum total leverage ratio	4.50
Minimum [Member] | Credit Agreement [Member]
Cash and Available Revolving Credit Capacity	$ 100
Maximum interest coverage ratio	3.50