Description of the business and recent developments: (Tables)

12 Months Ended

Dec. 31, 2021

Description of the business and recent developments:

Schedule of diluted weighted average shares

	Year Ended	Year Ended	Year Ended
	December 31,	December 31,	December 31,
	2021	2020	2019
Weighted average common shares—basic	46,419,180	45,947,772	45,542,315
Dilutive effect of stock options	34,007	80,849	32,222
Dilutive effect of restricted stock	510,733	639,577	505,858
Weighted average common shares—diluted	46,963,920	46,668,198	46,080,395

Schedule of unvested and anti-dilutive shares

	December 31,	December 31,	December 31,
	2021	2020	2019
Unvested shares of restricted common stock	1,253,321	1,339,596	1,283,281
Anti-dilutive options for common stock	45,809	32,324	39,608
Anti-dilutive shares of restricted common stock	86,619	223,118	348

Schedule of lease cost

		Year			Year
		Ended			Ended
	December 31, 2021			December 31, 2020
Finance lease cost amortization of right-of-use assets	$	26,424		$	22,850
Interest expense on finance lease liabilities		19,419			18,892
Operating lease cost		18,382			17,362
Total lease costs		64,225			59,104
Other lease information
Cash paid for amounts included in the measurement of lease liabilities
Operating cash flows from finance leases		(17,366)			(19,121)
Operating cash flows from operating leases		(20,194)			(18,664)
Financing cash flows from finance leases		(23,054)			(23,990)
Right-of-use assets obtained in exchange for new finance lease liabilities		50,831			71,622
Right-of-use assets obtained in exchange for new operating lease liabilities		17,853			35,659
Weighted-average remaining lease term — finance leases (in years)		12.6			12.4
Weighted-average remaining lease term — operating leases (in years)		18.7			20.2
Weighted average discount rate — finance leases		9.0	%		10.3	%
Weighted average discount rate — operating leases		5.4	%		5.6	%

Schedule of future minimum payments under operating lease agreements

The future minimum payments under these operating lease and finance lease agreements are as follows (in thousands):

	Operating		Finance
For the twelve months ending December 31,	Leases		Leases
2022	$	17,680	$	36,211
2023		18,359		35,417
2024		17,057		35,766
2025		14,562		30,519
2026		12,585		27,970
Thereafter		111,463		252,880
Total minimum lease obligations		191,706		418,763
Less—amounts representing interest		(67,715)		(172,893)
Present value of minimum lease obligations		123,991		245,870
Current maturities		(12,197)		(17,048)
Lease obligations, net of current maturities	$	111,794	$	228,822

Schedule of impact on financial statement line items from adopting ASC 326

			Current-period
	Balance at		Provision for		Write offs		Balance at
	Beginning		Expected Credit		Charged Against		End of
Description	of Period		Losses		Allowance		Period
Allowance for credit losses (deducted from accounts receivable)
Year ending December 31, 2021	$	1,921	$	5,595	$	(6,006)	$	1,510
Year ending December 31, 2020	$	1,771	$	4,997	$	(4,847)	$	1,921
Year ending December 31, 2019	$	1,263	$	6,190	$	(5,682)	$	1,771

Schedule of depreciation and amortization periods

Type of asset	Depreciation or amortization period
Indefeasible rights of use (IRUs)	Shorter of useful life or the IRU lease agreement; generally 15 to 20 years
Network equipment	3 to 8 years
Leasehold improvements	Shorter of lease term, including reasonably assured renewal periods, or useful life
Software	5 years
Owned buildings	40 years
Office and other equipment	3 to 7 years
System infrastructure	5 to 10 years