CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)
Service revenue	$ 347,979	$ 316,973	$ 305,500
Operating expenses:
Network operations (including $507, $529 and $510 of equity-based compensation expense, respectively, exclusive of amounts shown separately)	150,225	143,642	132,160
Selling, general, and administrative (including $8,212, $7,794 and $7,185 of equity-based compensation expense, respectively)	87,242	79,885	76,984
Depreciation and amortization	64,358	62,478	59,850
Total operating expenses	301,825	286,005	268,994
Operating income	46,154	30,968	36,506
Release of lease obligation			2,739
Interest income and other	2,630	1,851	848
Interest expense	(41,797)	(36,319)	(34,511)
Income (loss) before income taxes	6,987	(3,500)	5,582
Income tax benefit (expense)	49,702	(751)	1,960
Net income (loss)	56,689	(4,251)	7,542
Comprehensive income (loss):
Net income (loss)	56,689	(4,251)	7,542
Foreign currency translation adjustment	1,469	1,249	(1,626)
Comprehensive income (loss)	$ 58,158	$ (3,002)	$ 5,916
Basic net income (loss) per common share (in dollars per share)	$ 1.22	$ (0.09)	$ 0.17
Diluted net income (loss) per common share (in dollars per share)	$ 1.21	$ (0.09)	$ 0.17
Dividends declared per common share (in dollars per share)	$ 0.76	$ 0.21
Weighted-average common shares -basic (in shares)	46,286,735	45,514,844	45,180,485
Weighted-average common shares -diluted (in shares)	46,996,904	45,514,844	45,704,052