Acquisitions - Unaudited Pro Forma (Details) - Verizon [Member] - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2017
Business Acquisition [Line Items]
Revenues	$ 1,152,261	$ 3,309,381
Net income from operations	$ 80,135	$ 194,504
Basic EPS (in dollars per share)	$ 1.03	$ 2.50
Diluted EPS (in dollars per share)	$ 1.02	$ 2.48