Property and equipment: (Tables)

12 Months Ended

Dec. 31, 2016

Property and equipment:

Schedule of property and equipment

        Property and equipment consisted of the following (in thousands):

	December 31,
	2016			2015
Owned assets:
Network equipment	$	476,786		$	445,558
Leasehold improvements		182,734			169,245
System infrastructure		102,502			94,110
Software		9,523			9,400
Office and other equipment		13,735			12,855
Building		1,171			1,214
Land		99			103
		786,550			732,485
Less—Accumulated depreciation and amortization		(621,162	)		(571,429	)
		165,388			161,056
Assets under capital leases:
IRUs		349,920			337,626
Less—Accumulated depreciation and amortization		(153,667	)		(138,546	)
		196,253			199,080
Property and equipment, net	$	361,641		$	360,136