Capital Stock - Additional Information (Details) - USD ($) $ / shares in Units, $ in Millions				12 Months Ended
	Aug. 31, 2016	Jun. 24, 2016	May 02, 2016	Dec. 31, 2016	Dec. 31, 2015
Schedule Of Capitalization Equity [Line Items]
Common stock, par value				$ 0.0001	$ 0.0001
Preferred stock, par value				$ 0.0001	$ 0.0001
Convertible preferred stock, terms of conversion				Holders of the Series A Shares have the option to convert at any time after three years, or are mandatorily convertible after eight years.
Common stock, shares authorized				500,000,000	500,000,000
Preferred stock, shares authorized				50,000,000	50,000,000
Common stock, shares outstanding				155,138,637	149,862,000
Preferred stock, shares outstanding				0	0
Shares available for future issuance				344,861,363
Common Stock
Schedule Of Capitalization Equity [Line Items]
Additional shares issued				5,077,629
Proceeds from issuance of public offering, net of underwriting discounts and commissions		$ 54.8
Common Stock | Public Offering
Schedule Of Capitalization Equity [Line Items]
Additional shares issued		2,200,000
Public offering price		$ 26.01
Tower Cloud | Common Stock
Schedule Of Capitalization Equity [Line Items]
Issuance of shares	1,900,000
Common stock, par value	$ 0.0001
PEG Bandwidth, LLC | 3% Series A Convertible Preferred Stock
Schedule Of Capitalization Equity [Line Items]
Issuance of shares			87,500
Preferred stock, par value			$ 0.0001
Preferred stock, liquidation value			$ 87.5
Percentage of dividend rate on convertible preferred stock			3.00%
Preferred stock, liquidation preference			$ 1,000
PEG Bandwidth, LLC | Common Stock
Schedule Of Capitalization Equity [Line Items]
Issuance of shares			1,000,000
Common stock, par value			$ 0.0001
PEG Bandwidth, LLC | Common Stock | 3% Series A Convertible Preferred Stock
Schedule Of Capitalization Equity [Line Items]
Convertible preferred stock, conversion rate			28.5714
PEG Bandwidth, LLC | Common Stock | Maximum | 3% Series A Convertible Preferred Stock
Schedule Of Capitalization Equity [Line Items]
Convertible preferred stock, conversion rate			50.5305