Equity Investees (Schedule of Operations for Equity Investees) (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
INCOME STATEMENT DATA:
Revenues	$ 180,056	$ 191,078	$ 193,038
Operating Income	129,160	139,604	122,836
Net Income	$ 115,669	$ 134,479	$ 118,175

The amount of net income (loss) reported by an equity method investment of the entity.

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