Other Significant Transactions - Additional Information (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended		2 Months Ended		0 Months Ended		2 Months Ended	12 Months Ended	1 Months Ended
	Aug. 09, 2013	Aug. 09, 2013 NextRadio	Jan. 31, 2014 NextRadio	Feb. 28, 2014 NextRadio	Aug. 09, 2013 NextRadio Minimum wireless_device	Aug. 09, 2013 Emmis	Jan. 31, 2014 Emmis	Feb. 28, 2014 Emmis	Mar. 31, 2014 Emmis Subsequent Event
Long-term Purchase Commitment [Line Items]
Minimum number of devices with pre-loaded smartphone application					30,000,000
Period of agreement		3 years
Agreement amount		$ 15
Call option, maximum ownership interest allowed to be exercised by radio operator	30.00%
Agreement, payment remitted		3.75	3.75			0.80	0.40		0.10
Variable interest entity, consolidated, carrying amount of assets				0.8
Variable interest entity, liabilities				0.8
Expense recognized in period								$ 1.1