Condensed Consolidated Statements of Operations and Comprehensive Income (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Revenue:
Services	$ 76,217	$ 71,401	$ 149,647	$ 140,188
Subscriber equipment	20,333	19,815	40,490	37,146
Engineering and support services	5,971	3,468	10,416	6,539
Total revenue	102,521	94,684	200,553	183,873
Operating expenses:
Cost of services (exclusive of depreciation and amortization)	16,730	14,206	30,933	28,682
Cost of subscriber equipment	13,268	12,893	27,180	24,013
Research and development	4,645	1,741	6,766	3,400
Selling, general and administrative	18,493	18,399	37,679	36,764
Depreciation and amortization	19,672	18,597	39,938	36,828
Total operating expenses	72,808	65,836	142,496	129,687
Operating income	29,713	28,848	58,057	54,186
Other income (expense):
Interest income, net	725	641	1,362	1,278
Undrawn credit facility fees	(1,460)	(2,020)	(2,959)	(4,116)
Other expense, net	(3,789)	(869)	(4,139)	(2,265)
Total other expense	(4,524)	(2,248)	(5,736)	(5,103)
Income before income taxes	25,189	26,600	52,321	49,083
Provision for income taxes	(10,170)	(11,187)	(20,759)	(18,736)
Net income	15,019	15,413	31,562	30,347
Net income attributable to common stockholders	12,167	13,663	26,960	26,847
Weighted average shares outstanding - basic (in shares)	86,793	76,900	81,964	76,834
Weighted average shares outstanding - diluted (in shares)	95,653	87,530	86,444	87,477
Net income attributable to common stockholders per share - basic (in dollars per share)	$ 0.14	$ 0.18	$ 0.33	$ 0.35
Net income attributable to common stockholders per share - diluted (in dollars per share)	$ 0.14	$ 0.18	$ 0.32	$ 0.35
Comprehensive income:
Net income	15,019	15,413	31,562	30,347
Foreign currency translation adjustments, net of tax	274	(188)	430	(261)
Unrealized gain (loss) on marketable securities, net of tax	2	(271)	62	(285)
Comprehensive income	15,295	14,954	32,054	29,801
Series A Preferred Stock [Member]
Other income (expense):
Dividends, Preferred Stock, Total	1,750	1,750	3,500	3,500
Series B Preferred Stock [Member]
Other income (expense):
Dividends, Preferred Stock, Total	$ 1,102	$ 0	$ 1,102	$ 0