Commitments and contingencies: (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and contingencies:

Schedule of future minimum annual payments under capital leases-fiber lease agreements

The future minimum payments (principal and interest) under these agreements are as follows (in thousands):

For the year ending December 31,
2018	$	23,969
2019		22,953
2020		22,954
2021		22,491
2022		21,228
Thereafter		222,080
Total minimum lease obligations		335,675
Less—amounts representing interest		(178,171	)
Present value of minimum lease obligations		157,504
Current maturities		(7,171	)
Capital lease obligations, net of current maturities	$	150,333

Schedule of future minimum annual payments under operating leases and building access agreements

Future minimum annual payments under these arrangements are as follows (in thousands):

For the year ending December 31,
2018	$	37,276
2019		27,347
2020		22,170
2021		17,717
2022		11,875
Thereafter		35,538
	$	151,923