Quarterly financial information (unaudited): (Tables)

12 Months Ended

Dec. 31, 2015

Quarterly financial information (unaudited):

Schedule of quarterly financial information

	Three months ended
	March 31, 2014		June 30, 2014		September 30, 2014			December 31, 2014
	(in thousands, except share and per share amounts)
Service revenue	$	92,937	$	94,623	$	95,691		$	96,749
Network operations, including equity-based compensation expense		38,836		39,605		40,407			41,046
Gains on equipment transactions		2,295		2,731		3,114			2,810
Operating income		12,907		14,309		13,614			13,066
Net income (loss)		125		1,208		(184	)		(352	)
Net income (loss) per common share—basic and diluted		0.00		0.03		(0.00	)		(0.01	)
Weighted-average number of common shares—basic		46,409,735		45,897,449		45,629,079			45,229,125
Weighted-average number of common shares—diluted		46,907,360		46,294,966		45,629,079			45,229,125

	Three months ended
	March 31, 2015			June 30, 2015		September 30, 2015		December 31, 2015
	(in thousands, except share and per share amounts)
Service revenue	$	97,242		$	98,799	$	103,017	$	105,177
Network operations, including equity-based compensation expense		41,079			42,412		45,182		45,836
Gains on capital lease terminations		10,110			—		1,484		—
Gains on equipment transactions		1,548			719		1,152		2,023
Loss on debt extinguishment and redemption		(10,144	)		—		—		—
Operating income		10,487			10,810		15,519		16,174
Net (loss) income		(1,585	)		840		3,161		2,480
Net (loss) income per common share—basic and diluted		(0.04	)		0.02		0.07		0.06
Weighted-average number of common shares—basic		45,158,250			44,774,831		44,474,724		44,323,131
Weighted-average number of common shares—diluted		45,158,250			45,054,507		44,702,127		44,558,089