Lease Commitments - Narrative (Details) $ in Millions	9 Months Ended
	Sep. 30, 2016 USD ($) renewal_term	Sep. 30, 2015 USD ($)
Operating Leased Assets [Line Items]
Rent expense	$ 28.6	$ 12.7
Rental income	$ 5.3	$ 4.7
Towers [Member]
Operating Leased Assets [Line Items]
Number of renewals | renewal_term	4
Term of renewals	5 years
Towers [Member] | Minimum [Member]
Operating Leased Assets [Line Items]
Term of lease	5 years
Towers [Member] | Maximum [Member]
Operating Leased Assets [Line Items]
Term of lease	10 years
Other [Member] | Minimum [Member]
Operating Leased Assets [Line Items]
Term of lease	5 years
Other [Member] | Maximum [Member]
Operating Leased Assets [Line Items]
Term of lease	20 years