Asset Held for Sale - Additional Information (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) Building	Mar. 31, 2017 USD ($)
Long Lived Assets Held For Sale [Line Items]
Land, building and improvements, net book value	$ 1,377	$ 3,141
Assets held for sale
Long Lived Assets Held For Sale [Line Items]
Number of properties held for sale | Building	2
Land, building and improvements, net book value	$ 1,400
Reclassification of acquired spectrum from FCC licenses to assets held for sale		$ 1,800