Business Combinations and Asset Acquisitions - Summary of Estimated Fair Values of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Jul. 03, 2017	Jan. 31, 2017
Business Acquisition [Line Items]
Goodwill	$ 677,132	$ 673,729
NMS
Business Acquisition [Line Items]
Property, plant and equipment				$ 36,417
Accounts receivable				2,826
Other assets				1,623
Intangible assets				52,437
Accounts payable, accrued expenses and other liabilities				(8,895)
Intangible liabilities				(3,440)
Deferred income taxes				(18,403)
Total purchase consideration				$ 62,565
Southern Light, LLC
Business Acquisition [Line Items]
Property, plant and equipment			$ 279,467
Cash and cash equivalents			1,992
Accounts receivable			11,139
Goodwill			318,620
Other assets			1,287
Intangible assets			160,100
Accounts payable, accrued expenses and other liabilities			(19,846)
Deferred revenue			(38,134)
Deferred income taxes			(9,004)
Capital lease obligations			(3,189)
Total purchase consideration			702,432
Hunt Telecommunications, LLC
Business Acquisition [Line Items]
Property, plant and equipment			59,682
Cash and cash equivalents			3,181
Accounts receivable			4,906
Goodwill			96,425
Other assets			413
Intangible assets			73,000
Accounts payable, accrued expenses and other liabilities			(3,741)
Deferred revenue			(6,040)
Deferred income taxes			(40,391)
Capital lease obligations			(164)
Total purchase consideration			$ 187,271