PROPERTY AND EQUIPMENT: (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Property, Plant and Equipment, Gross	$ 138,690	$ 129,610
Less: Accumulated depreciation and amortization	(103,408)	(95,690)
Property and equipment, net	35,282	33,920
Land Improvements [Member]
Property, Plant and Equipment, Gross	3,777	3,777
Building Improvements [Member]
Property, Plant and Equipment, Gross	1,554	1,575
Property, Plant and Equipment, Useful Life	31 years
Transmitters and Towers [Member]
Property, Plant and Equipment, Gross	37,330	35,592
Transmitters and Towers [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life	7 years
Transmitters and Towers [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life	15 years
Equipment [Member]
Property, Plant and Equipment, Gross	49,694	47,278
Equipment [Member] | Minimum [Member]
Property, Plant and Equipment, Useful Life	3 years
Equipment [Member] | Maximum [Member]
Property, Plant and Equipment, Useful Life	7 years
Furniture and Fixtures [Member]
Property, Plant and Equipment, Gross	8,076	7,098
Property, Plant and Equipment, Useful Life	6 years
Software Development [Member]
Property, Plant and Equipment, Gross	16,393	14,035
Property, Plant and Equipment, Useful Life	3 years
Leaseholds and Leasehold Improvements [Member]
Property, Plant and Equipment, Gross	20,710	19,139
Property Plant And Equipment, Estimated Useful Life	Lease Term
Construction In Progress [Member]
Property, Plant and Equipment, Gross	$ 1,156	$ 1,116