Zayo 10-Q 8 Nov 13 2014 Q1 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	3 Months Ended
	Sep. 30, 2013
Document And Entity Information [Abstract]	'
Document Type	'10-Q
Amendment Flag	'false
Document Period End Date	30-Sep-13
Document Fiscal Year Focus	'2014
Document Fiscal Period Focus	'Q1
Entity Registrant Name	'Zayo Group LLC
Entity Central Index Key	'0001502756
Current Fiscal Year End Date	'--06-30
Entity Filer Category	'Non-accelerated Filer
Entity Common Stock, Shares Outstanding	0

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Sep. 30, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Current assets	'	'
Cash and cash equivalents	$92,433	$88,148
Trade receivables, net of allowance of $3,653 and $3,689 as of September 30, 2013 and June 30, 2013, respectively	62,536	67,811
Due from related parties	533	622
Prepaid expenses	18,673	19,188
Deferred income taxes, net	30,600	30,600
Other assets	1,989	2,851
Total current assets	206,764	209,220
Property and equipment, net	2,448,764	2,411,220
Intangible assets, net	627,194	636,258
Goodwill	685,284	682,775
Debt issuance costs, net	95,901	99,098
Deferred income taxes, net	53,732	60,036
Other assets	28,860	29,284
Total assets	4,146,499	4,127,891
Current liabilities	'	'
Current portion of long-term debt	16,200	16,200
Accounts payable	20,922	33,477
Accrued liabilities	112,440	115,932
Accrued interest	26,387	55,048
Capital lease obligations, current	7,612	6,600
Deferred revenue, current	54,613	35,977
Total current liabilities	238,174	263,234
Long-term debt, non-current	2,811,323	2,814,505
Capital lease obligations, non-current	15,685	6,567
Deferred revenue, non-current	334,386	326,180
Stock-based compensation liability	201,063	158,520
Deferred income taxes, net	7,374	5,560
Other long-term liabilities	19,775	19,892
Total liabilities	3,627,780	3,594,458
Commitments and contingencies (Note 10)	'	'
Member's equity	'	'
Member's interest	707,713	703,963
Accumulated other comprehensive income/(loss)	4,704	-4,755
Accumulated deficit	-193,698	-165,775
Total member's equity	518,719	533,433
Total liabilities and member's equity	$4,146,499	$4,127,891

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Sep. 30, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Statement of Financial Position [Abstract]	'	'
Trade receivables allowance	$3,653	$3,689

Condensed_Consolidated_Stateme

Condensed Consolidated Statements Of Operations (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012
Income Statement [Abstract]	'	'	'	'	'
Revenue	$264,345	'	'	'	$231,502
Operating costs and expenses	'	'	'	'	'
Operating costs, excluding depreciation and amortization	34,882	'	'	'	32,717
Selling, general and administrative expenses, excluding stock-based compensation	74,732	'	'	'	85,792
Stock-based compensation	42,684	'	'	'	10,481
Selling, general and administrative expenses	117,416	'	'	'	96,273
Depreciation and amortization	80,575	'	'	'	79,549
Total operating costs and expenses	232,873	'	'	'	208,539
Operating income	31,472	'	'	'	22,963
Other expenses	'	'	'	'	'
Interest expense	-51,497	'	'	'	-62,555
Loss on extinguishment of debt	0	'	'	'	-64,975
Other income, net	663	'	'	'	585
Total other expense, net	-50,834	'	'	'	-126,945
Loss from continuing operations before provision for income taxes	-19,362	'	'	'	-103,982
Provision/(benefit) for income taxes	8,534	9,460	6,519	-3,438	-36,588
Loss from continuing operations	-27,896	'	'	'	-67,394
Earnings from discontinued operations, net of income taxes	0	'	'	'	1,808
Net loss	($27,896)	($24,386)	($18,543)	($34,241)	($65,586)

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements Of Comprehensive Loss (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]	'	'
Net loss	($27,896)	($65,586)
Foreign currency translation adjustments	9,459	4,452
Comprehensive loss	($18,437)	($61,134)

Condensed_Consolidated_Stateme2

Condensed Consolidated Statement Of Member's Equity (USD $)	Total	Colocation Asset Purchase [Member]	Members Interest [Member]	Members Interest [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Other Comprehensive Loss [Member]	Accumulated Deficit [Member]	Accumulated Deficit [Member]
In Thousands				Colocation Asset Purchase [Member]		Colocation Asset Purchase [Member]		Colocation Asset Purchase [Member]
Balance at Jun. 30, 2013	$533,433	'	$703,963	'	($4,755)	'	($165,775)	'
Capital contributed (cash)	1,881	'	1,881	'	0	'	0	'
Preferred stock-based compensation	232	'	232	'	0	'	0	'
Foreign currency translation adjustments	9,459	'	0	'	9,459	'	0	'
Colocation asset purchase	'	1,637	'	1,637	'	0	'	0
Other	-27	'	0	'	0	'	-27	'
Net loss	-27,896	'	0	'	0	'	-27,896	'
Balance at Sep. 30, 2013	$518,719	'	$707,713	'	$4,704	'	($193,698)	'

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements Of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities	'	'
Net loss	($27,896)	($65,586)
Earnings from discontinued operations	0	1,808
Loss from continuing operations	-27,896	-67,394
Adjustments to reconcile net loss to net cash provided by operating activities	'	'
Depreciation and amortization	80,575	79,549
Loss on extinguishment of debt	0	64,975
Non-cash interest expense	6,512	8,642
Stock-based compensation	42,684	10,481
Amortization of deferred revenues	-12,139	-9,624
Additions to deferred revenue	24,032	2,899
Provision for bad debts	409	535
Deferred income taxes	8,603	-39,064
Changes in operating assets and liabilities, net of acquisitions	'	'
Trade receivables	5,604	-16,042
Prepaid expenses	1,612	4,946
Other assets	-2,307	-1,291
Accounts payable and accrued liabilities	-32,567	41,521
Payables to related parties, net	-140	-993
Other liabilities	-1,105	-70
Net cash provided by operating activities of continuing operations	93,877	79,070
Cash flows from investing activities	'	'
Purchases of property and equipment	-86,672	-70,163
Broadband stimulus grants received	0	3,507
Acquisitions, net of cash acquired	-294	-2,328,165
Net cash used in investing activities of continuing operations	-86,966	-2,394,821
Cash flows from financing activities	'	'
Equity contributions	1,881	337,203
Principal repayments on capital lease obligations	-397	-378
Principal repayments on long-term debt	-4,050	-697,475
Payment of early redemption fees on debt extinguished	0	-39,797
Proceeds from issuance of long-term debt	0	2,840,000
Payment of deferred debt issuance costs	-183	-82,508
Change in restricted cash, net	0	22,415
Cash contributed to ZPS (Note 3)	0	-2,424
Net cash (used in)/provided by financing activities of continuing operations	-2,749	2,377,036
Cash flows from continuing operations	4,162	61,285
Cash flows from discontinued operations	'	'
Operating activities	0	1,544
Cash flows from discontinued operations	0	1,544
Effect of changes in foreign exchange rates on cash	123	208
Net decrease in cash and cash equivalents	4,285	63,037
Cash and cash equivalents, beginning of period	88,148	150,693
Cash and cash equivalents, end of period	92,433	213,730
Supplemental disclosure of non-cash, investing and financing activities:	'	'
Cash paid for interest, net of capitalized interest	74,994	8,062
Cash paid for income taxes	485	568
Non-cash purchases of equipment through capital leasing	3,275	0
Increase in accruals for purchases of property and equipment	($14,228)	$11,449

Business_and_Basis_of_Presenta

Business and Basis of Presentation	3 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Business and Basis of Presentation	'
	BUSINESS AND BASIS OF PRESENTATION
	Business
	Zayo Group, LLC, a Delaware limited liability company, was formed on May 4, 2007 and is the operating parent company of a number of subsidiaries engaged in telecommunication and Internet infrastructure services. Zayo Group, LLC and its subsidiaries are collectively referred to as “Zayo Group” or the “Company.” Headquartered in Boulder, Colorado, the Company operates an integrated metropolitan and national fiber optic infrastructure in the United States and Europe to offer:
	•	Dark and lit bandwidth infrastructure services on metro, regional and national fiber networks.
	•	Colocation and connectivity services.
	•	Mobile infrastructure.
	Zayo Group is wholly owned by Zayo Group Holdings, Inc. (“Holdings”), which in turn is wholly-owned by Communications Infrastructure Investments, LLC (“CII”).
	Basis of Presentation
	The accompanying condensed consolidated financial statements include all the accounts of the Company and its wholly-owned subsidiaries. All inter-company accounts and transactions have been eliminated in consolidation. The accompanying condensed consolidated financial statements and related notes are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial reporting and pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”) for quarterly reports on Form 10-Q, and do not include all of the note disclosures required by GAAP for complete financial statements. These condensed consolidated financial statements should, therefore, be read in conjunction with the consolidated financial statements and notes thereto for the year ended June 30, 2013 included in the Company's Annual Report on Form 10-K filed with the SEC on September 23, 2013 (the “Annual Report”). In the opinion of management, all adjustments considered necessary for fair presentation of financial position, results of operations and cash flows of the Company have been included herein. The results of operations for the three month period ended September 30, 2013 are not necessarily indicative of the operating results for any future interim period or the full year.
	Unless otherwise noted, dollar amounts and disclosures throughout the notes to the condensed consolidated financial statements relate to the Company's continuing operations and are presented in thousands of dollars.
	The Company's fiscal year ends June 30 each year, and we refer to the fiscal year ended June 30, 2013 as “Fiscal 2013” and the fiscal year ending June 30, 2014 as “Fiscal 2014.”
	Significant Accounting Policies
	There have been no changes to the Company's significant accounting policies described in its Annual Report that have had a material impact on the Company's condensed consolidated financial statements and related notes.
	Use of Estimates
	The preparation of the Company's consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expense during the reporting period. Significant estimates are used when establishing allowances for doubtful accounts, reserves for disputed line cost billings, determining customer lives used to recognize certain revenues, determining useful lives for depreciation and amortization, determining accruals for exit activities associated with real estate leases, assessing the need for impairment charges (including those related to intangible assets and goodwill), determining the fair values of assets acquired and liabilities assumed in business combinations, accounting for income taxes and related valuation allowances against deferred tax assets and estimating the common units fair values used to compute stock-based compensation liability. Management evaluates these estimates and judgments on an ongoing basis and makes estimates based on historical experience, current conditions, and various other assumptions that are believed to be reasonable under the circumstances. The results of these estimates form the basis for making judgments about the carrying values of assets and liabilities as well as identifying and assessing the accounting treatment with respect to commitments and contingencies. Actual results may differ from these estimates under different assumptions or conditions.

Acquisitions

Acquisitions	3 Months Ended
	Sep. 30, 2013
Business Combinations [Abstract]	'
Acquisitions	'
	ACQUISITIONS
	As of September 30, 2013 and since the formation of Zayo Group, LLC in May 2007, the Company has consummated 26 transactions accounted for as business combinations. The consummation of the acquisitions was executed as part of the Company’s business strategy of expanding through acquisitions. The acquisitions of these businesses have allowed the Company to increase the scale at which it operates, which in turn affords the Company the ability to increase its operating leverage, extend its network reach, and broaden its customer base.
	The accompanying condensed consolidated financial statements include the operations of the acquired entities from their respective acquisition dates.
	Acquisitions Completed During Fiscal 2014
	The Company completed one acquisition during the first quarter of Fiscal 2014. The Company had not yet finalized its purchase accounting related to the acquired assets and assumed liabilities as of September 30, 2013 for the following acquisition:
	Colocation Asset Purchase
	On August 1, 2013, zColo entered into an asset purchase agreement with an undisclosed colocation business. The agreement was consummated on the same date, at which time zColo acquired substantially all of the net assets of this business for a purchase price of approximately $1,932, comprised of 301,949 preferred units with an estimated fair value of $1,637 and cash consideration of $344 ($294 net of cash acquired). The purchase price is subject to customary post-closing adjustments. $278 of the purchase price (consisting of 51,310 preferred units) is currently held in escrow pending expiration of the adjustment period. The cash consideration was paid with cash on hand.
	The results of the acquired colocation business are included in the Company's operating results beginning August 1, 2013.
	Acquisitions Completed During Fiscal 2013
	The Company completed 6 acquisitions during Fiscal 2013 with an aggregate purchase price of $2,485,809. The Company had not yet finalized its purchase accounting related to the acquired assets and assumed liabilities as of September 30, 2013 for the following acquisitions:
	First Telecom Services, LLC (“First Telecom”)
	On December 14, 2012, the Company acquired 100% of the equity interest in First Telecom, for total consideration of $109,700, subject to certain post-closing adjustments. $11,000 of the purchase price is currently held in escrow pending the expiration of the indemnification adjustment period. The acquisition cost was paid with cash on hand.
	The results of the acquired FTS business are included in the Company's operating results beginning December 14, 2012.
	Core NAP, L.P. (“Core NAP")
	On May 31, 2013, zColo entered into a purchase agreement with Core NAP. The agreement was consummated on the same date, at which time zColo acquired substantially all of the net assets of Core NAP for a purchase price of approximately $7,030, subject to customary post-closing adjustments. $1,095 of the purchase price is currently held in escrow pending the expiration of the indemnification adjustment period. The purchase price was paid with cash on hand.
	The results of the acquired Core NAP business are included in the Company's operating results beginning May 31, 2013.
	Pending and Recently Closed Acquisitions
	Acquisition of Access Communications, Inc. ("Access")
	On August 13, 2013, the Company entered into a purchase agreement with Access, a Minnesota corporation, and shareholders of Access, which closed on October 1, 2013. Zayo acquired 100% of the equity interest in Access. The purchase price, subject to certain customary post-closing adjustments, was $40,068 and was paid with cash on hand.
	Acquisition of FiberLink, LLC ("FiberLink")
	On October 2, 2013, the Company entered into a purchase agreement with FiberLink, an Illinois limited liability company, and the sellers of FiberLink. The agreement was consummated on the same date, at which time the Company acquired 100% of the equity interest in FiberLink. The purchase price of $43,000, subject to certain customary post-closing adjustments, was paid with available funds drawn on the Company's $250,000 Revolving Credit Facility.
	Acquisition Method Accounting Estimates
	The Company has recognized the assets and liabilities acquired from the aforementioned acquisitions based on its preliminary estimates of their acquisition date fair values. The determination of the fair values of the acquired assets and liabilities assumed (and the related determination of estimated lives of depreciable tangible and identifiable intangible assets) require significant judgment. As of September 30, 2013, the Company has not completed its fair value analysis and calculations in sufficient detail necessary to arrive at the final estimates of the fair value of the acquired assets and liabilities assumed, along with the related allocations to goodwill and intangible assets as it relates to its acquisitions of First Telecom, Core NAP, and the Colocation Asset Purchase. As such, all information presented as it relates to these acquisitions is preliminary and subject to revision pending the final fair value analysis. As additional information becomes known concerning the acquired net assets, management may make adjustments to the opening balance sheet of the acquired company up to the end of the measurement period, which is no longer than a one year period following the acquisition date. The table below reflects the Company’s estimates of the acquisition date fair values of the assets and liabilities assumed from its Fiscal 2013 and 2014 acquisitions for which acquisition accounting method is not yet finalized:
		First Telecom			Core NAP			Colocation Asset Purchase
	Acquisition date	December 14,			May 31,			August 1,
		2012			2013			2013
	Cash	$	—		$	50		$	50
	Other current assets	5,945			175			619
	Property and equipment	37,919			1,672			8,993
	Deferred tax assets, net	11,964			—			—
	Intangibles	35,516			—			—
	Goodwill	44,580			5,674			—
	Other assets	157			21			545
	Total assets acquired	136,081			7,592			10,207
	Current liabilities	4,560			279			719
	Deferred revenue	21,821			—			219
	Other liabilities	—			233			7,287
	Total liabilities assumed	26,381			512			8,225
	Net assets acquired	109,700			7,080			1,982
	Less cash acquired	—			(50		)	(50		)
	Net consideration paid	$	109,700		$	7,030		$	1,932
	The goodwill arising from the Company's acquisitions results from the synergies, anticipated incremental sales to the acquired company customer base and economies-of-scale expected from the acquisitions. The Company has allocated the goodwill to the reporting units (as such reporting units existed on the respective acquisition dates) that were expected to benefit from the acquired goodwill. The allocation was determined based on the excess of the fair value of the acquired business over the fair value of the individual assets acquired and liabilities assumed that were assigned to the reporting units. Note 4 - Goodwill, displays the allocation of the Company's acquired goodwill to each of its reporting units. The goodwill associated with the acquisition of First Telecom and Core NAP is deductible for tax purposes.
	In each of the Company's Fiscal 2013 and Fiscal 2014 acquisitions, the Company acquired certain customer relationships. These relationships represent a valuable intangible asset, as the Company anticipates continued business from the acquired customer bases. The Company's estimate of the fair value of the acquired customer relationships is based on a multi-period excess earnings valuation technique. The Company estimates the useful life of the acquired customer relationships to be approximately 18 years as it relates to the FTS acquired customer relationships. The Company has not yet completed an initial valuation of acquired customer relationships for the Core NAP and the Colocation Asset Purchase.
	Transaction Costs
	Transaction costs include expenses incurred that are directly related to potential and closed acquisitions. The Company incurred transaction costs of $587 during the three months ended September 30, 2013 and $11,383 during the three months ended September 30, 2012. Transaction costs have been included in selling, general and administrative expenses during these periods.
	Pro-forma Financial Information
	The unaudited pro forma results presented below include the effects of the Company’s Fiscal 2013 acquisitions of AboveNet, Fibergate, USCarrier, First Telecom, Litecast, and Core NAP and Fiscal 2014 acquisition of the Colocation Asset Purchase and the Access and FiberLink acquisitions that occurred subsequent to September 30, 2013 as if the acquisitions occurred on July 1, 2012. The pro forma loss for the quarters ended September 30, 2013 and 2012 includes the additional depreciation and amortization resulting from the adjustments to the value of property and equipment and intangible assets resulting from purchase accounting and adjustment to amortized revenue during Fiscal 2013 and 2014 as a result of the acquisition date valuation of acquired deferred revenue. The pro forma results also include interest expense associated with debt used to fund the acquisitions. The pro forma results do not include any anticipated synergies or other expected benefits of the acquisitions. The unaudited pro forma financial information below is not necessarily indicative of either future results of operations or results that might have been achieved had the acquisitions been consummated as of July 1, 2012.
		Three months ended September 30,
		2013			2012
	Revenue	$	267,865		$	255,636
	Loss from continuing operations	$	(27,232	)	$	(57,697	)

SpinOff_Of_Business

Spin-Off Of Business	3 Months Ended
	Sep. 30, 2013
Discontinued Operations and Disposal Groups [Abstract]	'
Spin-Off Of Business	'
	SPIN-OFF OF BUSINESS
	In connection with certain business combinations, the Company may acquire assets or liabilities that support products outside of the Company’s primary focus of providing bandwidth infrastructure services.
	On September 30, 2012, the Company completed a spin-off of ZPS, a professional service business unit acquired in the acquisition of AboveNet. The Company distributed all of the assets and liabilities of ZPS on the spin-off date to Holdings.
	Consistent with discontinued operations reporting provisions, management determined that it had discontinued all significant cash flows and continuing involvement with respect to the ZPS operations effective September 30, 2012. Therefore, for the three months ended September 30, 2012, the results of the operations of ZPS have been aggregated in a single caption entitled, “Earnings from discontinued operations, net of income taxes” in the accompanying condensed consolidated statements of operations.
	The Company continues to have ongoing contractual relationships with ZPS to provide ZPS with bandwidth capacity. The contractual relationships are based on agreements that were entered into at estimated market rates. During the quarter ended September 30, 2012, transactions with ZPS were eliminated upon consolidation. Subsequent to the spin-off date, transactions with ZPS have been included in the Company’s results of operations. See Note 12 — Related-Party Transactions, for a discussion of transactions with ZPS during the three months ended September 30, 2013.
	Earnings from discontinued operations, net of income taxes in the accompanying consolidated statements of operations are comprised of the following:
		Three months ended September 30,
		2013		2012
	Revenues	$	—	$	6,474
	Earnings before income taxes	—		3,011
	Income tax expense	—		1,203
	Earnings from discontinued operations, net of income taxes	$	—	$	1,808
	The earnings from discontinued operations, net of income taxes, is net of $1,544 of intercompany expenses, which ZPS recognized during the period from transactions with other Zayo Group subsidiaries.

Goodwill

Goodwill	3 Months Ended
	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Goodwill	'
	GOODWILL
	The Company’s goodwill balance was $685,284 and $682,775 as of September 30, 2013 and June 30, 2013, respectively.
	The Company's reporting units are comprised of its reportable segments, Zayo Dark Fiber ("Dark Fiber"), Zayo Wavelength Services ("Waves"), Zayo SONET Services ("SONET"), Zayo Ethernet Services ("Ethernet"), Zayo IP Services ("IP"), Zayo Mobile Infrastructure Group ("MIG"), and Zayo Colocation ("zColo"). The following table reflects the allocation of goodwill acquired in the Company's Fiscal 2013 and 2014 acquisitions (for which the measurement period is still open) to the Company's reportable units:
		Dark Fiber			Waves		SONET		Ethernet		IP		MIG		zColo		Total
	As of June 30, 2013	$	189,869		$	215,864	$	50,286	$	91,708	$	80,072	$	38,313	$	16,663	$	682,775
	Additions:
	First Telecom	(358		)	—		—		—		—		—		—		(358		)
	Core NAP	—			—		—		—		—		—		2		2
	Foreign currency translation	2,273			297		—		81		115		—		99		2,865
	As of September 30, 2013	$	191,784		$	216,161	$	50,286	$	91,789	$	80,187	$	38,313	$	16,764	$	685,284
	During the three months ended September 30, 2013, goodwill increased by $2,865 due to foreign currency movements impacting goodwill allocated to the U.K. operations. In addition, the Company recorded minor purchase accounting adjustments to acquisitions closed during the past twelve months, which resulted in a net decrease to goodwill of $356.

Intangible_Assets

Intangible Assets	3 Months Ended
	Sep. 30, 2013
Intangible Assets, Net (Excluding Goodwill) [Abstract]	'
Intangible Assets	'
	INTANGIBLE ASSETS
	Identifiable acquisition-related intangible assets as of September 30, 2013 and June 30, 2013 were as follows:
		Gross		Accumulated			Net
		Carrying		Amortization
		Amount
	30-Sep-13
	Finite-Lived Intangible Assets
	Customer relationships	$	714,965	$	(92,709	)	$	622,256
	Trade names	1,179		(737		)	442
	Underlying rights	1,075		(67		)	1,008
		717,219		(93,513		)	623,706
	Indefinite-Lived Intangible Assets
	Certifications	3,488					3,488
	Total	$	720,707	$	(93,513	)	$	627,194
	June 30, 2013
	Finite-Lived Intangible Assets
	Customer relationships	$	715,730	$	(84,570	)	$	631,160
	Trade names	1,179		(590		)	589
	Underlying rights	1,075		(54		)	1,021
		717,984		(85,214		)	632,770
	Indefinite-Lived Intangible Assets
	Certifications	3,488					3,488
	Total	$	721,472	$	(85,214	)	$	636,258

LongTerm_Debt

Long-Term Debt	3 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Long-Term Debt	'
	LONG-TERM DEBT
	On July 2, 2012, the Company and Zayo Capital Inc. ("Zayo Capital"), a 100% owned finance subsidiary of the Company that does not have independent assets or operations, issued $750,000 aggregate principal amount of 8.125% senior secured first-priority notes due 2020 (the "Senior Secured Notes") and $500,000 aggregate principal amount of 10.125% senior unsecured notes due 2020 (the "Senior Unsecured Notes", and together with the Senior Secured Notes, the “Notes”). On July 2, 2012, the Company also entered into a $250,000 senior secured revolving credit facility (the "Revolver") and a $1,620,000 senior secured term loan facility, issued at a $30,000 discount, which accrues interest at floating rates (the “Term Loan Facility”); the rate on the Term Loan Facility was initially subject to a floor of 7.125%.
	On October 5, 2012, the Company and Zayo Capital entered into a second amendment (the “Second Amendment”) to the agreement governing its Term Loan Facility (the "Credit Agreement"). Under the terms of the Second Amendment, effective October 5, 2012, the interest rate on the Company’s Term Loan Facility was adjusted to bear an interest rate at LIBOR plus 4.0%, which represented a decrease of 187.5 basis points from the original Credit Agreement. The Second Amendment set a floor on the Term Loan Facility’s interest rate at 5.25%. The Second Amendment also reduced the interest rate on the Revolver by 187.5 basis points.
	On February 27, 2013, the Company and Zayo Capital entered into a Fourth Amendment (the “Fourth Amendment”) to the Company's Credit Agreement. Under the terms of the Fourth Amendment, effective February 27, 2013, the interest rate on the Company’s Term Loan Facility was further adjusted to bear interest at LIBOR plus 3.5% (the “Term Loan LIBOR Spread”) with a minimum LIBOR rate of 1.0%. The amended terms represent a downward adjustment of 50 basis points on the Term Loan LIBOR Spread and a 25 basis point reduction in the minimum LIBOR rate from the Second Amendment. Under the terms of the Fourth Amendment, the Company’s Revolver will bear interest at LIBOR plus 3.00%, based on the Company’s current leverage ratio (the “Revolving Loan LIBOR Spread”), which represents a downward adjustment of 50 basis points on the Revolving Loan LIBOR Spread from the Second Amendment. The Fourth Amendment also amended certain terms and provisions of the Company's Credit Agreement, including removing the senior secured and total leverage maintenance covenants and increasing the total leverage ratio required to be met in order to incur certain additional indebtedness from 5.00:1.00 to 5.25:1.00 as a multiple of EBITDA (as11 defined in the Credit Agreement).
	The interest rate in effect on the Term Loan Facility as of September 30, 2013 and June 30, 2013 was 4.50%. The interest rates in effect for the Revolver as of September 30, 2013 and June 30, 2013 were 3.25% and 3.27%, respectively. The Revolver is subject to a commitment fee of 0.5% of the weighted-average unused capacity and outstanding letters of credit backed by the Revolver are subject to a 0.25% fee per annum. The Revolver has a maturity date of July 2017.
	The Term Loan Facility was issued at a discount of $30,000 and has a maturity date of July 2019. The issue discount is being amortized to interest expense over the term of the loan. The terms of the Term Loan Facility require the Company to make quarterly principal payments of $4,050 plus an annual payment of up to 50% of excess cash flow, as determined in accordance with the Credit Agreement.
	As of September 30, 2013, the balances of the Notes and Term Loan Facility were $1,250,000 and $1,577,523 (net of an unamortized discount of $22,227), respectively.
	As of June 30, 2013, the Company’s debt obligations included the notes with a balance of $1,250,000, a term loan with a balance of $1,580,705 (net of unamortized discount of $23,094) and $0 outstanding under the Company’s revolver.
	As of September 30, 2013, standby letters of credit were outstanding in the amount of $6,561 as of September 30, 2013, leaving $243,439 available under the Revolver as of September 30, 2013. Outstanding letters of credit backed by the Revolver accrue interest at a rate ranging from 2.0% to 3.0% plus LIBOR per annum based upon the Company’s leverage ratio.
	Debt covenants
	The Credit Agreement, as amended, contains a covenant that requires the Company to maintain a minimum fixed-charge coverage ratio. Pursuant to the Credit Agreement, the Company shall not permit its Fixed Charge Coverage Ratio, which is defined in the Credit Agreement as the ratio of the Company's annualized modified EBITDA (as defined in the Credit Agreement) during the most recent quarter minus Capital Expenditures (as defined in the Credit Agreement) for the twelve month period ended as of the end of each applicable fiscal quarter to interest expense for that same period to be less than the minimum ratio for the applicable period set forth below:
	Fiscal Quarters Ending	Minimum
		Ratio
	September 30, 2013, December 31, 2013, March 31, 2014 and June 30, 2014	1.75	to 1.0
	September 30, 2014, December 31, 2014 and March 31, 2015	2	to 1.0
	June 30, 2015, September 30, 2015 and December 31, 2015	2.25	to 1.0
	March 31, 2016, June 30, 2016 and September 30, 2016	2.5	to 1.0
	December 31, 2016 and for each fiscal quarter thereafter	2.75	to 1.0
	The Credit Agreement also requires the Company and its subsidiaries to comply with customary affirmative and negative covenants, including covenants restricting the ability of the Company and its subsidiaries, subject to specified exceptions, to incur additional indebtedness, make additional guaranties, incur additional liens on assets, or dispose of assets, pay dividends, or make other distributions, voluntarily prepay certain other indebtedness, enter into transactions with affiliated persons, make investments and amend the terms of certain other indebtedness.
	The Credit Agreement does not contain any restrictions on the ability of the Company's subsidiaries to pay dividends or transfer assets to the Company.
	The Credit Agreement contains customary events of default, including among others, non-payment of principal, interest, or other amounts when due, inaccuracy of representations and warranties, breach of covenants, cross default to certain other indebtedness, insolvency or inability to pay debts, bankruptcy, or a change of control.
	The indentures governing the Company's Notes limit any increase in the Company's secured indebtedness (other than certain forms of secured indebtedness expressly permitted under the indentures) to a pro forma secured debt ratio of 4.5 times the Company's previous quarter's annualized modified EBITDA and limit the Company's incurrence of additional indebtedness to a total indebtedness ratio of 5.25 times the previous quarter's annualized modified EBITDA.
	The Company was in compliance with all covenants associated with its debt agreements as of September 30, 2013 and June 30, 2013.
	Redemption rights
	At any time prior to July 1, 2015 (for the Senior Secured Notes) and July 1, 2016 (for the Senior Unsecured Notes), the Company may redeem all or part of the Notes at a redemption price equal to the sum of (i) 100% of the principal amount thereof, plus (ii) accrued interest and a "make-whole" premium, which is a lump sum payment derived from a formula based on the net present value of future coupon payments that will not be paid because of the early redemption.
	On or after July 1, 2015 (for the Senior Secured Notes) or July 1, 2016 (for the Senior Unsecured Notes) the Company may redeem all or part of the Notes, at the redemption prices (expressed as percentages of principal amount and set forth below), plus accrued and unpaid interest and additional interest, if any, thereon, to the applicable redemption date, subject to the rights of the holders of the Notes on the relevant record date to receive interest due on the relevant interest payment date, if redeemed during the 12-month period beginning on July 1 of the years indicated below:
	Year	Redemption Price
		(Senior Secured Notes)
	2015	104.06%
	2016	102.03%
	2017 and thereafter	100.00%
	Year	Redemption Price
		(Senior Unsecured Notes)
	2016	105.06%
	2017	102.53%
	2018 and thereafter	100.00%
	In the event of an equity offering to the public, at any time prior to July 1, 2015, the Company may redeem up to 35% of the aggregate principal amount of the Notes issued under each of the Company's indentures at a redemption price of 108.125% (for the Senior Secured Notes) and 110.25% (for the Senior Unsecured Notes) of the principal amount thereof, plus accrued and unpaid interest and additional interest, if any, thereon to the redemption date, subject to the rights of the holders of the Notes on the relevant record date to receive interest due on the relevant interest payment date, with the net cash proceeds of one or more equity offerings, provided that (i) at least 65% of the aggregate principal amount of the Notes issued under each indenture remains outstanding immediately after the occurrence of such redemption and (ii) the redemption occurs within 90 days of the date of the closing of such equity offering.
	The Company may purchase the Notes in open-market transactions, tender offers, or otherwise. The Company is not required to make any mandatory redemption or sinking fund payments with respect to the Notes.
	The Company may make prepayments on the Term Loan Facility at any time without incurring a premium charge.
	Debt issuance costs
	In connection with the Notes offering, Revolver and Term Loan Facility and the subsequent amendments thereto, the Company incurred debt issuance costs of $116,293. These costs are being amortized to interest expense over the respective terms of the underlying debt instruments using the effective interest method, unless extinguished earlier, at which time the related unamortized costs are to be immediately expensed.
	The balance of debt issuance costs as of September 30, 2013 and June 30, 2013 was $95,901 and $98,960, net of accumulated amortization of $14,863 and $11,482, respectively. The amortization of debt issuance costs is included on the condensed consolidated statements of cash flows within the caption “non-cash interest expense” along with the amortization or accretion of the premium and discount on the Company’s indebtedness and changes in the fair value of the Company's interest rate derivatives. Interest expense associated with the amortization of debt issuance costs was $3,381 during the three months ended September 30, 2013, and $3,003 during the three months ended September 30, 2012.
	Interest rate derivatives
	On August 13, 2012, the Company entered into interest rate swap agreements with an aggregate notional value of $750,000 and a maturity date of June 30, 2017. There were no up-front fees for these agreements. The contract states that the Company pays a 1.67% fixed rate of interest for the term of the agreement, beginning June 30, 2013. The counter party pays to the Company the greater of actual LIBOR or 1.25%. The Company entered into the swap arrangements to reduce the risk of increased interest costs associated with potential changes in LIBOR rates.
	Changes in the fair value of interest rate swaps are recorded as an increase or decrease in interest expense in the consolidated statements of operations for the applicable period. During the three months ended September 30, 2013 and 2012, $2,264 and $4,484 , respectively, was recorded as an increase in interest expense for the change in the fair value of the interest rate swaps. The fair value of the interest rate swaps of $378 and $2,642 is included in “Other long term assets” in the Company’s consolidated balance sheet as of September 30, 2013 and June 30, 2013, respectively.

Income_Taxes

Income Taxes	3 Months Ended
	Sep. 30, 2013
Income Tax Disclosure [Abstract]	'
Income Taxes	'
	INCOME TAXES
	The Company, a limited liability company, is taxed at the Holdings level. All income tax balances resulting from the operations of Zayo Group, on a separate return basis, are reflected in these financial statements.
	The Company’s effective income tax rate differs from what would be expected if the federal statutory rate were applied to earnings before income taxes primarily because of certain expenses that represent permanent differences between book and tax expenses and deductions, such as stock-based compensation expense, that are recorded as an expense for financial reporting purposes but are not deductible for tax purposes.
	A reconciliation of the actual income tax provision and the tax computed by applying the U.S. federal rate to the earnings before income taxes during the three month periods ended September 30, 2013 and 2012 are as follows:
		For the three months ended September 30,
		2013			2012
	Expected (benefit)/provision at statutory rate	$	(6,779	)	$	(36,391	)
	Increase due to:
	Non-deductible stock-based compensation	14,939			3,668
	State income taxes provision/(benefit), net of federal benefit	783			(4,639		)
	Transaction costs not deductible for tax purposes	192			910
	Foreign tax rate differential	(666		)	(459		)
	Other, net	65			323
	Provision/(benefit) for income taxes	$	8,534		$	(36,588	)
	Each interim period, management estimates the annual effective tax rate and applies that rate to its reported year-to-date earnings. The tax expense or benefit related to items for which management is unable to make reliable estimates or that are significant, unusual, or extraordinary items that will be separately reported, or reported net of their related tax effect, are individually computed and are recognized in the interim period in which those items occur. In addition, the effect of changes in enacted tax laws, tax rates or tax status is recognized in the interim period in which the change occurs.
	The computation of the annual estimated effective tax rate at each interim period requires certain estimates and significant judgments, including but not limited to the expected operating income for the year, projections of the proportion of income earned and taxed in various jurisdictions, permanent differences, and the likelihood of realizing deferred tax assets generated in both the current year and prior years. The accounting estimates used to compute the interim provision for income taxes may change as new events occur, more experience is acquired, additional information is obtained, or the tax environment changes. The effective tax rate is significantly affected by the amount of non-deductible stock-based compensation recognized during the year and given the significant assumptions inherent in the determination of this item, management is not able to reliably estimate the annual amount expected to impact the effective tax rate. As such, the tax effect of non-deductible stock-based compensation is recognized in each interim period in which the stock-based compensation is recorded.
	Updated Presentation of Fiscal Year 2013 Interim Financial Data
	During the first quarter of Fiscal 2014 in conjunction with preparing the Form 10-Q, the Company identified an immaterial error in its disclosure of quarterly financial information presented in the notes to the consolidated financial statements included in the 2013 Annual Report on Form 10-K. Specifically, when the Company recasted the final adjustments to its purchase accounting related to the AboveNet acquisition, it did not allocate the effect of income taxes to each interim period but rather recorded the entire amount to the fourth quarter 2013. The error did not impact the full year income tax (benefit)/provision nor the presentation and disclosure of income taxes paid. For comparative purposes, interim financial information reflecting the change in interim period presentation of the tax effects of AboveNet purchase accounting adjustments is presented below:
	(in thousands)	For the three months ended
		30-Sep-12			31-Dec-12			31-Mar-13			30-Jun-13
	Income tax (benefit)/provision, as originally stated	$	(27,320	)	$	6,025		$	13,305		$	(16,056	)
	Income tax effect of AboveNet fair value adjustments	(9,268		)	(9,463		)	(6,786		)	25,516
	Income tax (benefit)/provision, as adjusted	$	(36,588	)	$	(3,438	)	$	6,519		$	9,460
	Net (loss)/income, as originally stated	$	(74,854	)	$	(43,704	)	$	(25,329	)	$	1,130
	Income tax effect of AboveNet fair value adjustments	9,268			9,463			6,786			(25,516		)
	Net loss, as adjusted	$	(65,586	)	$	(34,241	)	$	(18,543	)	$	(24,386	)
	The interim financial information for the quarter ended September 30, 2012 has been adjusted accordingly in the Company's condensed consolidated statements of operations, comprehensive loss and cash flows, Note 13 - Segment Reporting, and Note 14 - Condensed Consolidating Financial Information and will be adjusted prospectively for the quarters ended December 31, 2012, March 31, 2013 and June 30, 2013. In addition, the reconciliation of the actual income tax (benefit)/provision and the tax computed by applying the U.S. federal tax rate to earnings before income taxes presented above has been retrospectively adjusted to conform to the revised presentation of income tax (benefit)/provision.

Equity

Equity	3 Months Ended
	Sep. 30, 2013
Stockholders' Equity Note [Abstract]	'
Equity	'
	EQUITY
	Zayo Group was initially formed on May 4, 2007, and is a wholly-owned subsidiary of Holdings, which in turn is wholly owned by CII. CII was organized on November 6, 2006, and subsequently capitalized on May 7, 2007, with capital contributions from various institutional and founder investors. Cash, property, and service proceeds from the capitalization of CII were contributed to the Company, and the contributions are reflected in the Company’s member’s equity. The Company is controlled by the CII Board of Directors, which is in turn controlled by the members of CII in accordance with the rights specified in the CII operating agreement.
	During the three months ended September 30, 2013, CII contributed $1,881 in cash to the Company. The source of the cash contribution was dividend payments received from CII's other subsidiaries.
	As discussed in Note 2 - Acquisitions, the Company issued 301,949 preferred units with an estimated fair value of $1,637 in connection with the Colocation Asset Purchase during the first quarter of Fiscal 2014. $278 of the purchase price (consisting of 51,310 preferred units) is currently held in escrow pending expiration of the adjustment period.

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	Sep. 30, 2013
Share-based Compensation [Abstract]	'
Stock-Based Compensation	'
	STOCK-BASED COMPENSATION
	Liability Classified Awards
	The Company has been given authorization by CII to award 525,000,000 of CII's common units as profits interests to employees, directors, and affiliates of the Company.
	As of September 30, 2013, CII had nine classes of common units with different liquidation preferences: Class A through Class I units. Common units are issued to employees and to independent directors of the Company and are allocated by the Chief Executive Officer and the board of managers on the terms and conditions specified in the employee equity agreement. The common units do not have voting rights. During the three months ended September 30, 2013, the Company issued 598,822 Class H common units to its independent directors and 45,767,059 Class I common units to its employees and independent directors. At September 30, 2013, 511,590,542 common units of CII were issued and outstanding to employees, directors, and affiliates of the Company and 13,409,458 common units of CII were available to be issued.
	The common units are considered to be stock-based compensation with terms that require the awards to be classified as liabilities due to cash settlement features. As such, the Company accounts for the vested awards as a liability and re-measures the liability to fair value at each reporting date until the date of settlement.
	As of September 30, 2013 and June 30, 2013, the estimated fair value of the common units was as follows:
		As of
	Common Unit Class	September 30, 2013		June 30, 2013
		(estimated per unit value)
	Class A	$	1.63	$	1.5
	Class B	1.46		1.34
	Class C	1.25		1.14
	Class D	1.21		1.1
	Class E	1.04		0.95
	Class F	0.93		0.75
	Class G	0.51		0.46
	Class H	0.43		0.38
	Class I	0.27		—
	The liability associated with the common units issued to employees and directors of the Company was $201,063 and $158,520 as of September 30, 2013 and June 30, 2013, respectively. As of September 30, 2013, common units with an estimated fair value of $139,582 were unvested. The fair value of the unvested common units will be recognized as stock-based compensation expense over the next three years.
	The stock-based compensation expense associated with the common units was $42,452 during the three months ended September 30, 2013 and $10,267 during the three months ended September 30, 2012.
	The Company's stock-based compensation relates to employees functioning in the selling, general and administrative capacity. The Company presents stock-based compensation as a separate component of selling, general and administrative expenses on the consolidated statement of operations due to the size and volatility of the non-cash expense.
	The holders of common units of CII are not entitled to transfer their units or receive dividends or distributions, except at the discretion of CII's Board of Directors. Upon a liquidation of CII, or upon a non-liquidating distribution, the holders of common units share in the proceeds after the capital contributions of the CII preferred unit holders plus their priority return of 6% per annum has been reimbursed. The remaining proceeds from a liquidation event are distributed between the preferred and common unit holders on a scale ranging from 85% to the preferred unit holders and 15% to the common unit holders to 80% to the preferred unit holders and 20% to the common unit holders. The percentage allocated to the common unit holders is dependent upon the return multiple realized by the preferred unit holders as defined in the CII operating agreement. The maximum incremental allocation of proceeds from a liquidation event to common unit holders, of 20%, occurs if the return multiple realized by a preferred unit holder reaches 3.5 times each respective preferred holder's combined capital contributions.
	Each class of common units has a liquidation threshold. Holders of a respective class of common units begin to receive a portion of the proceeds from a liquidity event once the aggregate distributions previously made with respect to issued common units of earlier classes are equal to or greater than the liquidation threshold of the respective common unit class. Common unit holders of each of the following classes begin sharing in the proceeds of a liquidation event once the total amount distributed to earlier classes reaches the following liquidation thresholds:
	Common Unit Class	Liquidation Threshold
	Class A	$	—
	Class B	15,000
	Class C	40,000
	Class D	45,000
	Class E	75,000
	Class F	95,000
	Class G	235,000
	Class H	290,000
	Class I	435,000
	Equity Classified Awards
	CII has issued preferred units to certain Zayo Group executives and independent directors as compensation. The terms of these preferred unit awards require the Company to record the award as an equity award. The Company estimates the fair value of these equity awards on the grant date and recognizes the related expense over the vesting period of the awards. As these awards have been issued by CII to employees and directors of the Company as compensation, the related expense has been recorded by the Company in the accompanying consolidated statements of operations. On July 1, 2013, 70,193 preferred unit awards were granted to the Company's independent directors with an estimated grant date fair value of $380, which will vest over a period of three years. The Company recognized stock-based compensation expense and a related increase to the Company's member's interest account of $232 for the three months ended September 30, 2013 and $214 for the three months ended September 30, 2012.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	FAIR VALUE MEASUREMENTS
	The Company’s financial instruments consist of cash and cash equivalents, restricted cash, trade receivables, accounts payable, interest rate swaps, long-term debt and stock-based compensation liability. The carrying values of cash and cash equivalents, restricted cash, trade receivables, and accounts payable approximated their fair values at September 30, 2013 and June 30, 2013 due to the short maturity of these instruments.
	The carrying value of the Company’s note obligations reflects the original amounts borrowed and was $1,250,000 as of September 30, 2013 and June 30, 2013. Based on market interest rates for debt of similar terms and average maturities, the fair value of the Company's notes as of September 30, 2013 and June 30, 2013 was estimated to be $1,319,675 and $1,364,375, respectively. The Company’s fair value estimates associated with its note obligations were derived utilizing Level 2 inputs – quoted prices for these instruments in less active markets.
	The carrying value of the Company’s term loan obligations reflects the original amounts borrowed, net of the unamortized discount and was $1,577,523 and $1,580,705 as of September 30, 2013 and June 30, 2013, respectively. The Company’s term loan accrues interest at variable rates based upon the one month, three month or six month LIBOR (with a LIBOR floor of 1.00%) plus a spread of 3.50%. Since management does not believe that the Company’s credit quality has changed significantly since the date when the amended Term Loan Facility was entered into in February 2013, its carrying amount approximates fair value. Excluding any offsetting effect of the Company's interest rate swaps, a hypothetical increase in the applicable interest rate on the Company’s term loan of one percentage point above the 1.0% LIBOR floor would increase the Company’s annual interest expense by approximately $15,998.
	The Company’s interest rate swaps are valued using discounted cash flow techniques that use observable market inputs, such as LIBOR-based yield curves, forward rates, and credit ratings. Changes in the fair value of the interest rate swaps of $2,264 and $4,484 were recorded as an increase to interest expense during the three months ended September 30, 2013 and 2012, respectively. A hypothetical increase in LIBOR rates of 100 basis points would increase the fair value of the interest rate swaps by approximately $22,050.
	The Company records its stock-based compensation liability at its estimated fair value. Financial instruments measured at fair value on a recurring basis are summarized below:
		Level	30-Sep-13		30-Jun-13
	Assets Recorded at Fair Value in the Financial Statements:
	Interest rate swap	Level 2	$	378	$	2,642
	Liabilities Recorded at Fair Value in the Financial Statements:
	Stock-based compensation liability	Level 3	$	201,063	$	158,520

Commitments_And_Contingencies

Commitments And Contingencies	3 Months Ended
	Sep. 30, 2013
Commitments and Contingencies Disclosure [Abstract]	'
Commitments And Contingencies	'
	COMMITMENTS AND CONTINGENCIES
	Purchase commitments
	At September 30, 2013, the Company was contractually committed for $93,391 of capital expenditures for construction materials and purchases of property and equipment. A majority of these purchase commitments are expected to be satisfied in the next twelve months. These purchase commitments are primarily success based; that is, the Company has executed customer contracts that support the future capital expenditures.
	Contingencies
	In the normal course of business, the Company is party to various outstanding legal proceedings, asserted and unasserted claims, and carrier disputes. In the opinion of management, the ultimate disposition of these matters, both asserted and unasserted, will not have a material adverse effect on the Company’s financial condition, results of operations, or cash flows.

Related_Party_Transactions

Related Party Transactions	3 Months Ended
	Sep. 30, 2013
Related Party Transaction, Due from (to) Related Party [Abstract]	'
Related Party Transactions	'
	RELATED PARTY TRANSACTIONS
	As of September 30, 2013 and June 30, 2013, the Company had a net receivable balance with Onvoy, Inc. ("Onvoy") in the amount of $533 and $622, respectively, related to services the Company provided to Onvoy.
	As discussed in Note 3 – Spin-off of Business, the Company spun-off the ZPS business, which was acquired in the AboveNet acquisition, to Holdings on September 30, 2012. The receivable from ZPS relates to the net working capital surplus of $10,447 on the spin-off date that was transferred to ZPS and was subsequently reimbursed to the Company during Fiscal 2013.
	Revenue and expenses associated with transactions with Onvoy and ZPS (subsequent to its September 30, 2012 spin-off date) have been recorded in the Company’s results from continuing operations. The following table represents the revenue and expense transactions recognized with Onvoy and ZPS during the three months ended September 30, 2013 and 2012:
		For the Three Months Ended
		September 30,
		2013			2012
	Revenue	$	3,052		$	1,699
	Operating costs	(125		)	(166		)
	Selling, general and administrative expenses	(241		)	(160		)
	Net	$	2,686		$	1,373
	On July 2, 2012, Matthew Erickson, the President of Zayo Fiber and Transport Infrastructure ("zFTI"), purchased $600 in aggregate principal amount of the Company’s 10.125% senior unsecured notes due 2020 at the offering price for such notes stated in the Company’s private notes offering. Mr. Erickson qualifies as an “accredited investor” (as defined in Rule 501 under the Securities Act) and purchased the notes on terms available to other investors. The notes were outstanding as of September 30, 2013.

Segment_Reporting

Segment Reporting	3 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]	'
Segment Reporting	'
	SEGMENT REPORTING
	The Company uses the management approach to determine the segment financial information that should be disaggregated and presented separately within the Company's footnotes to its financial statements presented in its filings on Form 10-Q and Form 10-K with the SEC. The management approach is based on the manner by which management has organized the segments within the Company for making operating decisions, allocating resources, and assessing performance.
	Prior to January 1, 2013, the Company had operated as three segments (also referred to herein as Strategic Product Groups): Zayo Bandwidth ("ZB"), Zayo Colocation ("zColo"), and Zayo Fiber Solutions ("ZFS"). Each Strategic Product Group is structured to provide sales, delivery, and customer support for its specific telecom and Internet infrastructure services. The ZB Strategic Product Group offered primarily lit bandwidth infrastructure services, the zColo Strategic Product Group provided colocation and inter-connection transport services and the Dark Fiber Strategic Product Group is dedicated to marketing and supporting dark fiber related services. Effective January 1, 2013, the Company implemented certain changes to its Strategic Product Group structure that had the impact of disaggregating the lit bandwidth services group (ZB) into its constituent lit bandwidth services and changed the name of the legacy ZFS group to Zayo Dark Fiber.
	As of June 30, 2013, the Company has seven Strategic Product Groups as described below:
	•Zayo Dark Fiber ("Dark Fiber"). Through the Dark Fiber Strategic Product Group, the Company provides dark fiber and related services on portions of the fiber network and on newly constructed network. The Company provides dark fiber pairs to customers, who then light the fiber using their own optronic equipment, allowing the customer to manage bandwidth on their own metropolitan and long haul networks according to their specific business needs. As part of this service offering, the Company manages and maintains the underlying fiber network for the customer. Other related services may include the installation and maintenance of building entrance fiber or riser fiber for distribution within a building. Customers include carriers and other communication service providers, Internet service providers, wireless service providers, major media and content companies, large enterprises, and other companies that have the expertise to run their own fiber optic networks. The Company markets and sells dark fiber-related services under long-term contracts (averaging approximately fifteen years in length); customers either pay upfront for the fiber (generally referred to as an IRU or Indefeasible Right to Use) or on a monthly basis for the fiber. Fiber maintenance (or O&M) is generally paid on an annual or monthly recurring basis regardless of the form of the payment for the provision of the fiber. Recurring payments are fixed but many times include automatic annual price escalators intended to compensate for inflation.
	•Zayo Wavelength Services ("Waves"). Through the Waves Strategic Product Group, the Company provides lit bandwidth infrastructure services to customers utilizing optical wavelength technology.  From a technological standpoint, the service is provided by multiplexing a number of optical customer signals onto different wavelengths (i.e., colors) of laser light. The Waves segment provides wavelength services in speeds of 1 Gbps, 2.5 Gbps, 10 Gbps, 40 Gbps, and 100 Gbps. The Waves Strategic Product Group also provides a dedicated wavelength service; that is, wavelengths on fibers that are not shared by between customers. Customers include carriers, financial services companies, healthcare, government institutions, education institutions and other enterprises. Services are typically provided for terms between one and five years for a fixed recurring monthly fee and in some cases an additional upfront, non-recurring fee.
	•Zayo SONET Services ("SONET"). The Company's Synchronous Optical Network Strategic Product Group provides lit bandwidth infrastructure services to its customers utilizing SONET technology. SONET is a standardized protocol that transfers multiple digital bit streams over optical fiber using lasers or highly coherent light from light-emitting diodes. SONET technology is often used to support private line services. This protocol enables transmission of voice, data and video at high speeds. SONET networks are protected, which provides for virtually instantaneous restoration of service in the event of a fiber cut or equipment failure. Services are provided in speeds ranging from DS-1 (1.54 Mbps) to OC-192 (10 Gbps) of capacity. Customers are largely carriers. Services are typically provided for terms between one and five years for a fixed recurring monthly fee and in some cases an additional upfront, non-recurring fee.
	•Zayo Ethernet Services ("Ethernet"). The Company's Ethernet Strategic Product Group provides lit bandwidth infrastructure services to its customers utilizing Ethernet technology.  Ethernet services are offered in metropolitan markets as well as between metropolitan areas (intercity) in point to point and multi-point configurations.  Unlike data transmission over a Waves network, information transmitted over Ethernet is transferred in a packet or frame across the network.  The frame enables the data to navigate across a shared infrastructure in order to reach the intended destination. Services are provided in speeds ranging from 10 Mbps to 10 Gbps. Customers include carriers, financial services companies, healthcare, government institutions, education institutions and other enterprises. Services are typically provided for terms between one and ten years for a fixed recurring monthly fee and in some cases an additional upfront, non-recurring fee.
	•Zayo Internet Protocol Services ("IP"). The Company's Internet Protocol Strategic Product Group provides lit bandwidth infrastructure services to its customers utilizing Internet Protocol technology. IP technology transports data across multiple circuits from the source to the destination. Information leaving the source is divided into several packets and each packet traverses the network utilizing the most efficient path and means. Packets of information may travel across different physical circuits or paths in order to reach the destination, at which point the packets are reassembled to form the complete communication. Services are generally used to exchange or access traffic on the public Internet. Services are provided in speeds ranging from 10 Mbps to 100 Gbps on a single port interface. Customers include regional telecommunications and cable carriers, enterprises, educational institutions and content companies. Services are typically provided for terms between one and ten years for a fixed recurring monthly fee and in some cases an additional upfront, non-recurring fee. Pricing is generally a function of bandwidth capacity and transport required to carry traffic from customer location to an Internet gateway.
	•Zayo Mobile Infrastructure ("MIG"). The Company's Mobile Infrastructure Strategic Product Group provides two key services:  Fiber-to-the-Tower ("FTT") and Small Cell Infrastructure.  The Company's FTT products consist of fiber based backhaul from cellular towers to mobile switching centers.  This service is generally provided in speeds of 50 Mbps and above and is used by wireless service providers to enable 3 G and 4 G cellular services.  The segment's Small Cell Infrastructure services provide two separate sub-services.  The first sub-service is neutral space and power, similar to a provider of mobile and broadcast tower space.  Wireless services providers purchase this service to provide them with a physical location to mount their small cell antennas.  The second sub-service is dark fiber backhaul from the antenna to a mobile switching center. The MIG customers are wireless carriers. Services are typically provided for terms between five and twenty years for a fixed recurring monthly fee and, in most cases, an additional upfront, non-recurring fee. Pricing is a function of the quantity of dark fiber consumed and the number of neutral space and power locations provided.
	•Zayo Colocation ("zColo"). Through the zColo Strategic Product Group, the Company provides network-neutral colocation and connectivity services in 25 data center and interconnection facilities across 19 markets throughout the United States.The zColo group manages approximately 175,000 square feet of billable colocation space as of September 30, 2013 within these 25 facilities. All facilities provide 24 hour per day, 365 days per year management and monitoring with physical security, fire suppression, power distribution, backup power, cooling and multiple redundant fiber connections to many major networks. The components of the Company's network neutral colocation offering are: space, power, interconnection and remote technical services. The Company sells space in half-racks, racks, cabinets, cages, and private suites and provides alternating current (“AC”) and direct current (“DC”) power at various levels. The power product is backed up by batteries and generators. As a network-neutral provider of colocation services, the Company provides customers with interconnection services, allowing customers to connect and deliver capacity services between separate networks using fiber, Ethernet, SONET, DS3 and DS1 service levels. The Company believes the interconnection offering is differentiated by intra-building dark fiber infrastructure connecting multiple suites in major U.S. carrier hotel locations and the Metro Interconnect product that allows customers to interconnect to other important traffic exchange buildings within a metro market leveraging the metro fiber network. The Company also offers data center customers outsourced technical resources through “remote hands” product. Customers can purchase packages of time or use technical staff on an as-needed basis. Customers vary somewhat by facility with a significant portion of the Group's revenue coming from customers requiring a high degree of connectivity and that choose to colocate in key carrier hotel and regional aggregation hub facilities. These customers include: domestic and foreign carriers, Internet service providers, cloud services providers, on-line gaming companies, content providers and CDN, media companies and other connectivity focused enterprise customers. Services are typically provided for terms between one and ten years for a recurring monthly fee and, in many cases, an additional upfront, non-recurring fee.
	Effective January 1, 2013, revenues for all of the Company’s products are included in one of the Company's seven Strategic Product Groups. The results of operations for each Strategic Product Group include an allocation of certain corporate related overhead costs. The allocation is based on a percentage that represents management’s estimate of the relative burden each segment bears of corporate overhead costs. Identifiable assets for each Strategic Product Group are reconciled to total consolidated assets including unallocated corporate assets and intercompany eliminations. Unallocated corporate assets consist primarily of cash, deferred tax assets, and deferred debt issuance costs.
	The following tables summarize significant financial information of each of the segments:
		As of and for the three months ended September 30, 2013
		Dark Fiber			Waves			SONET		Ethernet			IP			MIG		zColo			Corp/			Total
																					elimination
	Revenue	$	78,859		$	63,273		$	31,612	$	36,143		$	23,829		$	18,945	$	18,935		$	—		$	271,596
	Intersegment revenue	(11		)	(4,801		)	—		(14		)	(16		)	—		(2,409		)				(7,251		)
	Revenue from external customers	78,848			58,472			31,612		36,129			23,813			18,945		16,526			—			264,345
	Adjusted EBITDA	54,285			32,935			14,973		20,380			14,252			11,477		7,057			—			155,359
	Total assets	1,818,043			804,643			195,227		410,476			236,958			333,841		111,137			236,174			4,146,499
	Capital expenditures, net of stimulus grant reimbursements	23,218			22,063			935		13,127			5,361			19,169		2,799			—			86,672
		As of and for the three months ended September 30, 2012
		Dark Fiber			Waves			SONET		Ethernet			IP			MIG		zColo			Corp/			Total
																					elimination
	Revenue	$	67,732		$	57,826		$	32,252	$	31,085		$	21,460		$	14,193	$	15,296		$	—		$	239,844
	Intersegment revenue	(632		)	(5,245		)	—		(130		)	(180		)	—		(2,155		)	—			(8,342		)
	Revenue from external customers	67,100			52,581			32,252		30,955			21,280			14,193		13,141			—			231,502
	Adjusted EBITDA	46,433			26,839			14,328		15,359			10,998			7,448		4,549			(1,543		)	124,411
	Total assets	1,680,130			711,092			196,964		373,152			207,417			292,518		85,160			505,307			4,051,740
	Capital expenditures, net of stimulus grant reimbursements	19,459			15,911			419		8,388			2,459			16,670		3,350			—			66,656
	Adjusted EBITDA
	The Company defines Adjusted EBITDA as earnings/(loss) from continuing operations before interest, income taxes, depreciation and amortization (“EBITDA”) adjusted to exclude acquisition-related transaction costs, stock-based compensation, and certain non-cash or non-recurring items. The Company uses Adjusted EBITDA to evaluate operating performance, and this financial measure is among the primary measures used by management for planning and forecasting of future periods. The Company believes that the presentation of Adjusted EBITDA is relevant and useful for investors because it allows investors to view results in a manner similar to the method used by management and facilitates comparison of the Company’s results with the results of other companies that have different financing and capital structures.
	The Company also monitors Adjusted EBITDA because it has debt covenants that restrict its borrowing capacity that are based on a leverage ratio, which utilizes a modified EBITDA, as defined in the Company’s credit agreements. The modified EBITDA is consistent with the Company’s definition of Adjusted EBITDA, except that the later includes the pro forma Adjusted EBITDA of and expected synergies from the companies acquired by the Company during the quarter in which the debt compliance certification is due. The indentures governing the Company's Notes limit any increase in the Company's secured indebtedness (other than certain forms of secured indebtedness expressly permitted under the indentures) to a pro forma secured debt ratio of 4.5 times the previous quarter's annualized modified EBITDA and limit the Company's incurrence of additional indebtedness to a total indebtedness ratio of 5.25 times the previous quarter's annualized modified EBITDA, which is consistent with the incurrence restrictions in the Company's Credit Agreement governing its Term Loan Facility.
	Adjusted EBITDA results, along with other quantitative and qualitative information, are also utilized by the Company and its compensation committee for purposes of determining bonus payouts to employees.
	Adjusted EBITDA has limitations as an analytical tool and should not be considered in isolation from, or as a substitute for, analysis of the Company's results from operations and operating cash flows as reported under GAAP. For example, Adjusted EBITDA:
	•	does not reflect capital expenditures, or future requirements for capital and major maintenance expenditures or contractual commitments;
	•	does not reflect changes in, or cash requirements for, working capital needs;
	•	does not reflect the significant interest expense, or the cash requirements necessary to service the interest payments, on the Company's debt; and
	•	does not reflect cash required to pay income taxes.
	The Company’s computation of Adjusted EBITDA may not be comparable to other similarly titled measures computed by other companies because all companies do not calculate Adjusted EBITDA in the same fashion. Reconciliations from net earnings/(loss) to Adjusted EBITDA by segment and on a consolidated basis are as follows:
	Reconciliation from net earnings/(loss) to Adjusted EBITDA
		Three months ended September 30, 2013
		Dark Fiber			Waves			SONET		Ethernet			IP			MIG		zColo			Corp/			Zayo Group
																					elimination
	Net earnings/(loss)	$	8,579		$	11,550		$	6,998	$	9,493		$	9,393		$	3,154	$	2,717		$	(79,780	)	$	(27,896	)
	Interest expense	20			45			3		5			2			5		413			51,004			51,497
	Provision for income taxes	—			—			—		—			—			—		—			8,534			8,534
	Depreciation and amortization expense	39,914			16,818			5,380		7,356			2,682			5,915		2,510			—			80,575
	Transaction costs	22			23			5		20			8			15		494			—			587
	Stock-based compensation	5,750			4,499			2,587		3,506			2,167			2,388		923			20,864			42,684
	Foreign currency gain on intercompany loans	—			—			—		—			—			—		—			(622		)	(622		)
	Adjusted EBITDA	$	54,285		$	32,935		$	14,973	$	20,380		$	14,252		$	11,477	$	7,057		$	—		$	155,359
		Three months ended September 30, 2012
		Dark Fiber			Waves			SONET		Ethernet			IP			MIG		zColo			Corp/			Zayo Group
																					elimination
	Net earnings/(loss)	$	6,813		$	4,074		$	7,765	$	3,515		$	6,898		$	247	$	743		$	(95,641	)	$	(65,586	)
	Earnings from discontinued operations, net of taxes	—			—			—		—			—			—		—			(1,808		)	(1,808		)
	Interest expense	35			61			11		15			5			11		—			62,417			62,555
	Provision for income taxes	—			—			—		—			—			—		—			(36,588		)	(36,588		)
	Depreciation and amortization expense	35,771			19,310			5,442		9,281			2,689			5,005		2,051			—			79,549
	Transaction costs	2,436			2,240			570		1,980			878			1,682		1,597			—			11,383
	Stock-based compensation	1,378			1,154			540		568			528			503		158			5,652			10,481
Loss on extinguishment of debt	—			—			—		—			—			—		—			64,975			64,975
Foreign currency gain on intercompany loans	—			—			—		—			—			—		—			(550		)	(550		)
Adjusted EBITDA	$	46,433		$	26,839		$	14,328	$	15,359		$	10,998		$	7,448	$	4,549		$	(1,543	)	$	124,411

Condensed_Consolidating_Financ

Condensed Consolidating Financial Information	3 Months Ended
	Sep. 30, 2013
Condensed Consolidating Financial Information [Abstract]	'
Condensed Consolidating Financial Information	'
	CONDENSED CONSOLIDATING FINANCIAL INFORMATION
	As discussed in Note 6 – Long-Term Debt, on July 2, 2012, the Company co-issued, with its 100% owned finance subsidiary, Zayo Capital, Inc., $750,000 Senior Secured Notes and $500,000 Senior Unsecured Notes. The Notes are fully and unconditionally guaranteed, jointly and severally, on a senior secured basis by all of the Company’s current and future domestic restricted subsidiaries. Zayo Capital does not have independent assets or operations. The non-guarantor subsidiaries consist of the foreign subsidiaries that were acquired in conjunction with the Company's acquisition of AboveNet.
	The accompanying condensed consolidating financial information has been prepared and is presented to display the components of the Company’s balance sheets, statements of operations and statements of cash flows in a manner that allows an existing or future holder of the Company’s Notes to review and analyze the current financial position and recent operating results of the legal subsidiaries that guarantee the Company’s debt obligations.
	The operating activities of the separate legal entities included in the Company’s consolidated financial statements are interdependent. The accompanying condensed consolidating financial information presents the results of operations, financial position and cash flows of each legal entity. Zayo Group and its guarantors provide services to each other during the normal course of business. These transactions are eliminated in the consolidated results of operations of the Company. Activity related to income taxes is included at the issuer, or Zayo Group, LLC, level and is not allocated to the Company's guarantor and non-guarantor subsidiaries in the condensed consolidated financial information presented below.
	Condensed Consolidating Balance Sheets (Unaudited)
	September 30, 2013
		Zayo Group,			Guarantor			Non-			Eliminations				Total
		LLC			Subsidiaries			Guarantor
								Subsidiaries
		(Issuer)
	Assets
	Current assets
	Cash and cash equivalents	$	88,146		$	1,013		$	3,274		$	—			$	92,433
	Trade receivables, net	40,920			5,122			16,494			—				62,536
	Due from related parties	533			—			—			—				533
	Prepaid expenses	13,519			2,239			2,915			—				18,673
	Deferred income taxes	30,600			—			—			—				30,600
	Other assets	1,931			6			52			—				1,989
	Total current assets	175,649			8,380			22,735			—				206,764
	Property and equipment, net	2,291,534			61,893			95,337			—				2,448,764
	Intangible assets, net	575,681			18,036			33,477			—				627,194
	Goodwill	620,456			15,058			49,770			—				685,284
	Debt issuance costs, net	95,901			—			—			—				95,901
	Deferred income taxes, net	53,732			—			—			—				53,732
	Other assets	24,305			3,750			805			—				28,860
	Related party receivable, long-term	10,500			—			—			(10,500		)		—
	Investment in subsidiary	231,567			—			—			(231,567		)		—
	Total assets	$	4,079,325		$	107,117		$	202,124		$	(242,067	)		$	4,146,499
	Liabilities and member’s equity
	Current liabilities
	Current portion of long-term debt	$	16,200		$	—		$	—		$	—			$	16,200
	Accounts payable	17,550			923			2,449			—				20,922
	Accrued liabilities	98,246			5,968			8,226			—				112,440
	Accrued interest	26,387			—			—			—				26,387
	Capital lease obligations, current	1,881			5,731			—			—				7,612
	Due to related parties	(2,198		)	—			2,198			—				—
	Deferred revenue, current	51,671			882			2,060			—				54,613
	Total current liabilities	209,737			13,504			14,933			—				238,174
	Long-term debt, non-current	2,811,323			—			—			—				2,811,323
	Related party debt, long-term	—			—			10,500			(10,500		)		—
	Capital lease obligations, non-current	5,865			9,820			—			—				15,685
	Deferred revenue, non-current	327,212			3,920			3,254			—				334,386
	Stock-based compensation liability	195,279			3,703			2,081			—				201,063
	Deferred income taxes, net	—			—			7,374			—				7,374
	Other long-term liabilities	11,190			8,517			68			—				19,775
	Total liabilities	3,560,606			39,464			38,210			(10,500		)		3,627,780
	Member’s equity
	Member’s interest	755,407			33,874			149,999			(231,567		)		707,713
	Accumulated other comprehensive income	—			—			4,704			—				4,704
	(Accumulated deficit)/retained earnings	(236,688		)	33,779			9,211			—				(193,698		)
	Total member’s equity	518,719			67,653			163,914			(231,567		)		518,719
	Total liabilities and member’s equity	$	4,079,325		$	107,117		$	202,124		$	(242,067	)		$	4,146,499
	Condensed Consolidating Balance Sheets (Unaudited)
	June 30, 2013
		Zayo Group,			Guarantor			Non-			Eliminations					Total
		LLC			Subsidiaries			Guarantor
								Subsidiaries
		(Issuer)
	Assets
	Current assets
	Cash and cash equivalents	$	83,608		$	1,009		3,531			$	—				$	88,148
	Trade receivables, net	52,377			4,284			11,150			—					67,811
	Due from related parties	2,113			—			(384		)	(1,107		)			622
Prepaid expenses	14,768			1,634			2,786			—					19,188
Deferred income taxes	30,600			—			—			—					30,600
Restricted cash	—			—			—			—					—
Other assets, current	2,843			6			2			—					2,851
Total current assets	186,309			6,933			17,085			(1,107		)			209,220
Property and equipment, net	2,274,764			48,673			87,783			—					2,411,220
Intangible assets, net	585,590			18,695			31,973			—					636,258
Goodwill	620,812			15,055			46,908			—					682,775
Debt issuance costs, net	99,098			—			—			—					99,098
Deferred income taxes, net	60,036			—			—			—					60,036
Other assets	25,332			3,130			822			—					29,284
Related party receivable, long-term	10,427			—			—			(10,427		)			—
Investment in subsidiary	216,224			—			—			(216,224		)			—
Total assets	$	4,078,592		$	92,486		184,571			$	(227,758	)			$	4,127,891
Liabilities and member’s equity
Current liabilities
Current portion of long-term debt	$	16,200		$	—		$	—		$	—				$	16,200
Accounts payable	30,319			1,536			1,622			—					33,477
Accrued liabilities	103,780			5,376			6,776			—					115,932
Accrued interest	55,048			—			—			—					55,048
Capital lease obligations, current	1,493			5,107			—			—					6,600
Due to related-parties	25			—			1,082			(1,107		)			—
Deferred revenue, current	33,170			701			2,106			—					35,977
Total current liabilities	240,035			12,720			11,586			(1,107		)			263,234
Long-term debt, non-current	2,814,505			—			—			—					2,814,505
Related party debt, long-term	—			—			10,427			(10,427		)			—
Capital lease obligations, non-current	6,487			80			—			—					6,567
Deferred revenue, non-current	318,188			3,850			4,142			—					326,180
Deferred income taxes, net	—			—			5,560			—			—		5,560
Stock-based compensation liability	154,435			2,794			1,291			—					158,520
Other long-term liabilities	11,511			8,311			70			—					19,892
Total liabilities	3,545,161			27,755			33,076			(11,534		)			3,594,458
Member’s equity
Member’s interest	736,439			33,748			150,000			(216,224		)			703,963
Accumulated other comprehensive loss	—			—			(4,755		)	—					(4,755		)
(Accumulated deficit)/retained earnings	(203,008		)	30,983			6,250			—					(165,775		)
Total member’s equity	533,431			64,731			151,495			(216,224		)			533,433
Total liabilities and member’s equity	$	4,078,592		$	92,486		184,571			$	(227,758	)			$	4,127,891
Condensed Consolidating Statements of Operations (Unaudited)
For the three months ended September 30, 2013
	Zayo Group,			Guarantor			Non-			Eliminations				Total
	LLC			Subsidiaries			Guarantor
							Subsidiaries
	(Issuer)
Revenue	$	230,821		$	18,709		$	14,815		$	—			$	264,345
Operating costs and expenses
Operating costs, excluding depreciation and amortization	24,880			8,536			1,466			—				34,882
Selling, general and administrative expenses, excluding stock-based compensation	65,513			3,732			5,487			—				74,732
Stock-based compensation	41,078			909			697			—				42,684
Selling, general and administrative expenses	106,591			4,641			6,184			—				117,416
Depreciation and amortization	74,972			2,325			3,278			—				80,575
Total operating costs and expenses	206,443			15,502			10,928			—				232,873
Operating income	24,378			3,207			3,887			—				31,472
Other expenses
Interest expense	(51,013		)	(412		)	(72		)	—				(51,497		)
Other income, net	39			1			623			—				663
Equity in net earnings of subsidiaries	5,787			—			—			(5,787		)		—
Total other (expenses)/income, net	(45,187		)	(411		)	551			(5,787		)		(50,834		)
(Loss)/earnings before provision for income taxes	(20,809		)	2,796			4,438			(5,787		)		(19,362		)
Provision for income taxes	7,087			—			1,447			—				8,534
(Loss)/earnings from continuing operations	(27,896		)	2,796			2,991			(5,787		)		(27,896		)
Earnings from discontinued operations, net of income taxes	—			—			—			—				—
Net (loss)/earnings	$	(27,896	)	$	2,796		$	2,991		$	(5,787	)		$	(27,896	)
Condensed Consolidating Statements of Operations (Unaudited)
For the three months ended September 30, 2012
	Zayo Group,			Guarantor			Non-			Eliminations				Total
	LLC			Subsidiaries			Guarantor
							Subsidiaries
	(Issuer)
Revenue	$	201,919		$	15,072		$	14,511		$	—			$	231,502
Operating costs and expenses
Operating costs, excluding depreciation and amortization	23,115			7,696			1,906			—				32,717
Selling, general and administrative expenses, excluding stock-based compensation	73,434			4,451			7,907			—				85,792
Stock-based compensation	10,125			154			202			—				10,481
Selling, general and administrative expenses	83,559			4,605			8,109			—				96,273
Depreciation and amortization	74,207			2,049			3,293			—				79,549
Total operating costs and expenses	180,881			14,350			13,308			—				208,539
Operating income	21,038			722			1,203			—				22,963
Other expenses
Interest expense	(62,443		)	3			(115		)	—				(62,555		)
Loss on extinguishment of debt	(64,975		)	—			—			—				$	(64,975	)
Other income, net	35			—			550			—				585
Equity in net earnings of subsidiaries	1,362			—			—			(1,362		)		—
Total other expense, net	(126,021		)	3			435			(1,362		)		(126,945		)
(Loss)/earnings from continuing operations before provision for income taxes	(104,983		)	725			1,638			(1,362		)		(103,982		)
Provision/(benefit) for income taxes	(37,589		)	—			1,001			—				(36,588		)
Loss from continuing operations	(67,394		)	725			637			(1,362		)		(67,394		)
Earnings from discontinued operations, net of income taxes	1,808			—			—			—				1,808
Net (loss)/earnings	$	(65,586	)	$	725		$	637		$	(1,362	)		$	(65,586	)
Condensed Consolidating Statements of Cash Flows (Unaudited)
For the three months ended September 30, 2013
	Zayo Group,			Guarantor			Non-			Total
	LLC			Subsidiaries			Guarantor
							Subsidiaries
	(Issuer)
Net cash provided by operating activities	$	83,383		$	7,521		$	2,973		$	93,877
Cash flows from investing activities:
Purchases of property and equipment	(80,520		)	(2,799		)	(3,353		)	(86,672		)
Acquisitions, net of cash acquired	—			(294		)	—			(294		)
Net cash used in investing activities	(80,520		)	(3,093		)	(3,353		)	(86,966		)
Cash flows from financing activities:
Equity contributions	1,881			—			—			1,881
Principal repayments on long-term debt	(4,050		)	—			—			(4,050		)
Principal repayments on capital lease obligations	(251		)	(146		)	—			(397		)
Debt issuance costs, net of early redemption fees	(183		)	—			—			(183		)
Net cash provided by/(used in) financing activities	1,675			(4,424		)	—			(2,749		)
Effect of changes in foreign exchange rates on cash	—			—			123			123
Net increase/(decrease) in cash and cash equivalents	4,538			4			(257		)	4,285
Cash and cash equivalents, beginning of period	83,608			1,009			3,531			88,148
Cash and cash equivalents, end of period	$	88,146		$	1,013		$	3,274		$	92,433
Condensed Consolidating Statements of Cash Flows (Unaudited)
For the three months ended September 30, 2012
	Zayo Group,			Guarantor			Non-			Total
	LLC			Subsidiaries			Guarantor
							Subsidiaries
Net cash provided by/(used in) operating activities	$	71,435		$	5,202		$	2,433		$	79,070
Cash flows from investing activities:
Purchases of property and equipment, net of stimulus grants	(61,901		)	(3,253		)	(1,502		)	(66,656		)
Acquisitions, net of cash acquired	(2,336,057		)	—			7,892			(2,328,165		)
Net cash used in investing activities	(2,397,958		)	(3,253		)	6,390			(2,394,821		)
Cash flows from financing activities:
Equity contributions	337,203			—			—			337,203
Principal repayments on capital lease obligations	(378		)	—			—			(378		)
Principal repayments on long-term debt	(697,475		)	—			—			(697,475		)
Payment of early redemption fees on debt extinguished	(39,797		)	—			—			(39,797		)
Dividend received/(paid)	636			(636		)	—			—
Proceeds from borrowings	2,840,000			—			—			2,840,000
Changes in restricted cash	22,415			—			—			22,415
Cash contributed to ZPS	(2,424		)	—			—			(2,424		)
Payment of deferred debt issuance costs	(82,508		)	—			—			(82,508		)
Net cash provided by/(used in) financing activities	2,377,672			(636		)	—			2,377,036
Cash flows from discontinued operations
Cash flows from discontinued operations	1,544			—			—			1,544
Effect of changes in foreign exchange rates on cash	—			—			208			208
Net increase in cash and cash equivalents	52,692			1,313			9,032			63,037
Cash and cash equivalents, beginning of period	149,574			1,119			—			150,693
Cash and cash equivalents, end of period	$	202,266		$	2,432		$	9,032		$	213,730

Subsequent_Events

Subsequent Events	3 Months Ended
	Sep. 30, 2013
Subsequent Events [Abstract]	'
Subsequent Events	'
	SUBSEQUENT EVENTS
	Distribution to Common Unit Holders
	In September 2013, the Board of CII authorized a non-liquidating cash distribution to certain common unit holders of up to $10,000. The eligibility for receiving proceeds from this distribution was determined by the liquidation preference of the unit holder. Receiving proceeds from the authorized distribution was at the election of the common unit holder. As a condition of the early distribution, common unit holders electing to receive an early distribution received 90% of the amount that they would otherwise be entitled to receive if the distribution were in connection with a liquidating distribution. The common unit holders electing to receive the early distribution will retain all of their common units and be entitled to receive future distributions only to the extent such future distributions are in excess of the non-liquidating distribution, before applying the 10% discount. During October 2013, $9,865 was distributed to the Company’s common unit holders as a result of the non-liquidating distributions. The distribution was paid by CII and will be reflected in the Company’s Consolidated Statement of Member’s Equity as a non-cash capital contribution and corresponding reduction in the stock-based compensation liability. Common unit holders electing to receive the early distribution forfeited $1,096 in previously recognized stock-based compensation, which had the effect of reducing stock-based compensation expense recognized during the second quarter of Fiscal 2014.
	Pending and Recently Closed Acquisitions
	See Note 2 – Acquisitions, for a discussion of acquisitions that have closed subsequent to September 30, 2013.

Business_and_Basis_of_Presenta1

Business and Basis of Presentation (Policy)	3 Months Ended
	Sep. 30, 2013
Organization, Consolidation and Presentation of Financial Statements [Abstract]	'
Basis Of Presentation	'
	Basis of Presentation
	The accompanying condensed consolidated financial statements include all the accounts of the Company and its wholly-owned subsidiaries. All inter-company accounts and transactions have been eliminated in consolidation. The accompanying condensed consolidated financial statements and related notes are unaudited and have been prepared in accordance with accounting principles generally accepted in the United States (“GAAP”) for interim financial reporting and pursuant to the rules and regulations of the Securities and Exchange Commission (the “SEC”) for quarterly reports on Form 10-Q, and do not include all of the note disclosures required by GAAP for complete financial statements. These condensed consolidated financial statements should, therefore, be read in conjunction with the consolidated financial statements and notes thereto for the year ended June 30, 2013 included in the Company's Annual Report on Form 10-K filed with the SEC on September 23, 2013 (the “Annual Report”). In the opinion of management, all adjustments considered necessary for fair presentation of financial position, results of operations and cash flows of the Company have been included herein. The results of operations for the three month period ended September 30, 2013 are not necessarily indicative of the operating results for any future interim period or the full year.
	Unless otherwise noted, dollar amounts and disclosures throughout the notes to the condensed consolidated financial statements relate to the Company's continuing operations and are presented in thousands of dollars.
	The Company's fiscal year ends June 30 each year, and we refer to the fiscal year ended June 30, 2013 as “Fiscal 2013” and the fiscal year ending June 30, 2014 as “Fiscal 2014.”
Significant Accounting Policies	'
	Significant Accounting Policies
	There have been no changes to the Company's significant accounting policies described in its Annual Report that have had a material impact on the Company's condensed consolidated financial statements and related notes.
Use Of Estimates	'
	Use of Estimates
	The preparation of the Company's consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, and disclosures of contingent assets and liabilities at the date of the financial statements and the reported amounts of revenue and expense during the reporting period. Significant estimates are used when establishing allowances for doubtful accounts, reserves for disputed line cost billings, determining customer lives used to recognize certain revenues, determining useful lives for depreciation and amortization, determining accruals for exit activities associated with real estate leases, assessing the need for impairment charges (including those related to intangible assets and goodwill), determining the fair values of assets acquired and liabilities assumed in business combinations, accounting for income taxes and related valuation allowances against deferred tax assets and estimating the common units fair values used to compute stock-based compensation liability. Management evaluates these estimates and judgments on an ongoing basis and makes estimates based on historical experience, current conditions, and various other assumptions that are believed to be reasonable under the circumstances. The results of these estimates form the basis for making judgments about the carrying values of assets and liabilities as well as identifying and assessing the accounting treatment with respect to commitments and contingencies. Actual results may differ from these estimates under different assumptions or conditions.

Acquisitions_Tables

Acquisitions (Tables)	3 Months Ended
	Sep. 30, 2013
Business Combinations [Abstract]	'
Schedule of Acquisitions	'
	The table below reflects the Company’s estimates of the acquisition date fair values of the assets and liabilities assumed from its Fiscal 2013 and 2014 acquisitions for which acquisition accounting method is not yet finalized:
		First Telecom			Core NAP			Colocation Asset Purchase
	Acquisition date	December 14,			May 31,			August 1,
		2012			2013			2013
	Cash	$	—		$	50		$	50
	Other current assets	5,945			175			619
	Property and equipment	37,919			1,672			8,993
	Deferred tax assets, net	11,964			—			—
	Intangibles	35,516			—			—
	Goodwill	44,580			5,674			—
	Other assets	157			21			545
	Total assets acquired	136,081			7,592			10,207
	Current liabilities	4,560			279			719
	Deferred revenue	21,821			—			219
	Other liabilities	—			233			7,287
	Total liabilities assumed	26,381			512			8,225
	Net assets acquired	109,700			7,080			1,982
	Less cash acquired	—			(50		)	(50		)
	Net consideration paid	$	109,700		$	7,030		$	1,932
Schedule Of Pro-Forma Financial Information (Unaudited)	'
	The unaudited pro forma financial information below is not necessarily indicative of either future results of operations or results that might have been achieved had the acquisitions been consummated as of July 1, 2012.
		Three months ended September 30,
		2013			2012
	Revenue	$	267,865		$	255,636
	Loss from continuing operations	$	(27,232	)	$	(57,697	)

SpinOff_Of_Business_Tables

Spin-Off Of Business (Tables)	3 Months Ended
	Sep. 30, 2013
Discontinued Operations and Disposal Groups [Abstract]	'
Schedule Of Earnings From Discontinued Operations	'
	Earnings from discontinued operations, net of income taxes in the accompanying consolidated statements of operations are comprised of the following:
		Three months ended September 30,
		2013		2012
	Revenues	$	—	$	6,474
	Earnings before income taxes	—		3,011
	Income tax expense	—		1,203
	Earnings from discontinued operations, net of income taxes	$	—	$	1,808

Goodwill_Tables

Goodwill (Tables)	3 Months Ended
	Sep. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'
Schedule Of Goodwill	'
	The following table reflects the allocation of goodwill acquired in the Company's Fiscal 2013 and 2014 acquisitions (for which the measurement period is still open) to the Company's reportable units:
		Dark Fiber			Waves		SONET		Ethernet		IP		MIG		zColo		Total
	As of June 30, 2013	$	189,869		$	215,864	$	50,286	$	91,708	$	80,072	$	38,313	$	16,663	$	682,775
	Additions:
	First Telecom	(358		)	—		—		—		—		—		—		(358		)
	Core NAP	—			—		—		—		—		—		2		2
	Foreign currency translation	2,273			297		—		81		115		—		99		2,865
	As of September 30, 2013	$	191,784		$	216,161	$	50,286	$	91,789	$	80,187	$	38,313	$	16,764	$	685,284

Intangible_Assets_Tables

Intangible Assets (Tables)	3 Months Ended
	Sep. 30, 2013
Intangible Assets, Net (Excluding Goodwill) [Abstract]	'
Schedule Of Intangible Assets	'
	Identifiable acquisition-related intangible assets as of September 30, 2013 and June 30, 2013 were as follows:
		Gross		Accumulated			Net
		Carrying		Amortization
		Amount
	30-Sep-13
	Finite-Lived Intangible Assets
	Customer relationships	$	714,965	$	(92,709	)	$	622,256
	Trade names	1,179		(737		)	442
	Underlying rights	1,075		(67		)	1,008
		717,219		(93,513		)	623,706
	Indefinite-Lived Intangible Assets
	Certifications	3,488					3,488
	Total	$	720,707	$	(93,513	)	$	627,194
	June 30, 2013
	Finite-Lived Intangible Assets
	Customer relationships	$	715,730	$	(84,570	)	$	631,160
	Trade names	1,179		(590		)	589
	Underlying rights	1,075		(54		)	1,021
		717,984		(85,214		)	632,770
	Indefinite-Lived Intangible Assets
	Certifications	3,488					3,488
	Total	$	721,472	$	(85,214	)	$	636,258

LongTerm_Debt_Tables

Long-Term Debt (Tables)	3 Months Ended
	Sep. 30, 2013
Debt Disclosure [Abstract]	'
Schedule Of Fixed-Charge Coverage Ratios	'
	Pursuant to the Credit Agreement, the Company shall not permit its Fixed Charge Coverage Ratio, which is defined in the Credit Agreement as the ratio of the Company's annualized modified EBITDA (as defined in the Credit Agreement) during the most recent quarter minus Capital Expenditures (as defined in the Credit Agreement) for the twelve month period ended as of the end of each applicable fiscal quarter to interest expense for that same period to be less than the minimum ratio for the applicable period set forth below:
	Fiscal Quarters Ending	Minimum
		Ratio
	September 30, 2013, December 31, 2013, March 31, 2014 and June 30, 2014	1.75	to 1.0
	September 30, 2014, December 31, 2014 and March 31, 2015	2	to 1.0
	June 30, 2015, September 30, 2015 and December 31, 2015	2.25	to 1.0
	March 31, 2016, June 30, 2016 and September 30, 2016	2.5	to 1.0
	December 31, 2016 and for each fiscal quarter thereafter	2.75	to 1.0
Schedule Of Debt Instrument Redemption Price	'
	On or after July 1, 2015 (for the Senior Secured Notes) or July 1, 2016 (for the Senior Unsecured Notes) the Company may redeem all or part of the Notes, at the redemption prices (expressed as percentages of principal amount and set forth below), plus accrued and unpaid interest and additional interest, if any, thereon, to the applicable redemption date, subject to the rights of the holders of the Notes on the relevant record date to receive interest due on the relevant interest payment date, if redeemed during the 12-month period beginning on July 1 of the years indicated below:
	Year	Redemption Price
		(Senior Secured Notes)
	2015	104.06%
	2016	102.03%
	2017 and thereafter	100.00%
	Year	Redemption Price
		(Senior Unsecured Notes)
	2016	105.06%
	2017	102.53%
	2018 and thereafter	100.00%

Income_Taxes_Tables

Income Taxes (Tables)	3 Months Ended
	Sep. 30, 2013
Schedule Of Reconciliation Of Income Tax Provision	'
	A reconciliation of the actual income tax provision and the tax computed by applying the U.S. federal rate to the earnings before income taxes during the three month periods ended September 30, 2013 and 2012 are as follows:
		For the three months ended September 30,
		2013			2012
	Expected (benefit)/provision at statutory rate	$	(6,779	)	$	(36,391	)
	Increase due to:
	Non-deductible stock-based compensation	14,939			3,668
	State income taxes provision/(benefit), net of federal benefit	783			(4,639		)
	Transaction costs not deductible for tax purposes	192			910
	Foreign tax rate differential	(666		)	(459		)
	Other, net	65			323
	Provision/(benefit) for income taxes	$	8,534		$	(36,588	)
AboveNet [Member]	'
Schedule Of Purchase Accounting Adjustments To Prior Periods	'
	For comparative purposes, interim financial information reflecting the change in interim period presentation of the tax effects of AboveNet purchase accounting adjustments is presented below:
	(in thousands)	For the three months ended
		30-Sep-12			31-Dec-12			31-Mar-13			30-Jun-13
	Income tax (benefit)/provision, as originally stated	$	(27,320	)	$	6,025		$	13,305		$	(16,056	)
	Income tax effect of AboveNet fair value adjustments	(9,268		)	(9,463		)	(6,786		)	25,516
	Income tax (benefit)/provision, as adjusted	$	(36,588	)	$	(3,438	)	$	6,519		$	9,460
	Net (loss)/income, as originally stated	$	(74,854	)	$	(43,704	)	$	(25,329	)	$	1,130
	Income tax effect of AboveNet fair value adjustments	9,268			9,463			6,786			(25,516		)
	Net loss, as adjusted	$	(65,586	)	$	(34,241	)	$	(18,543	)	$	(24,386	)

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	Sep. 30, 2013
Share-based Compensation [Abstract]	'
Schedule Of Estimated Fair Value Of Common Units	'
	As of September 30, 2013 and June 30, 2013, the estimated fair value of the common units was as follows:
		As of
	Common Unit Class	September 30, 2013		June 30, 2013
		(estimated per unit value)
	Class A	$	1.63	$	1.5
	Class B	1.46		1.34
	Class C	1.25		1.14
	Class D	1.21		1.1
	Class E	1.04		0.95
	Class F	0.93		0.75
	Class G	0.51		0.46
	Class H	0.43		0.38
	Class I	0.27		—
Common Unit Liquidation Thresholds By Stock Series	'
	Common unit holders of each of the following classes begin sharing in the proceeds of a liquidation event once the total amount distributed to earlier classes reaches the following liquidation thresholds:
	Common Unit Class	Liquidation Threshold
	Class A	$	—
	Class B	15,000
	Class C	40,000
	Class D	45,000
	Class E	75,000
	Class F	95,000
	Class G	235,000
	Class H	290,000
	Class I	435,000

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Sep. 30, 2013
Fair Value Disclosures [Abstract]	'
Schedule Of Financial Instruments Measured At Fair Value On A Recurring Basis	'
	The Company records its stock-based compensation liability at its estimated fair value. Financial instruments measured at fair value on a recurring basis are summarized below:
		Level	30-Sep-13		30-Jun-13
	Assets Recorded at Fair Value in the Financial Statements:
	Interest rate swap	Level 2	$	378	$	2,642
	Liabilities Recorded at Fair Value in the Financial Statements:
	Stock-based compensation liability	Level 3	$	201,063	$	158,520

Related_Party_Transactions_Tab

Related Party Transactions (Tables)	3 Months Ended
	Sep. 30, 2013
Related Party Transaction, Due from (to) Related Party [Abstract]	'
Schedule Of Transactions Recognized With Related Parties	'
	The following table represents the revenue and expense transactions recognized with Onvoy and ZPS during the three months ended September 30, 2013 and 2012:
		For the Three Months Ended
		September 30,
		2013			2012
	Revenue	$	3,052		$	1,699
	Operating costs	(125		)	(166		)
	Selling, general and administrative expenses	(241		)	(160		)
	Net	$	2,686		$	1,373

Segment_Reporting_Tables

Segment Reporting (Tables)	3 Months Ended
	Sep. 30, 2013
Segment Reporting [Abstract]	'
Summary Of Significant Financial Information	'
	The following tables summarize significant financial information of each of the segments:
		As of and for the three months ended September 30, 2013
		Dark Fiber			Waves			SONET		Ethernet			IP			MIG		zColo			Corp/			Total
																					elimination
	Revenue	$	78,859		$	63,273		$	31,612	$	36,143		$	23,829		$	18,945	$	18,935		$	—		$	271,596
	Intersegment revenue	(11		)	(4,801		)	—		(14		)	(16		)	—		(2,409		)				(7,251		)
	Revenue from external customers	78,848			58,472			31,612		36,129			23,813			18,945		16,526			—			264,345
	Adjusted EBITDA	54,285			32,935			14,973		20,380			14,252			11,477		7,057			—			155,359
	Total assets	1,818,043			804,643			195,227		410,476			236,958			333,841		111,137			236,174			4,146,499
	Capital expenditures, net of stimulus grant reimbursements	23,218			22,063			935		13,127			5,361			19,169		2,799			—			86,672
		As of and for the three months ended September 30, 2012
		Dark Fiber			Waves			SONET		Ethernet			IP			MIG		zColo			Corp/			Total
																					elimination
	Revenue	$	67,732		$	57,826		$	32,252	$	31,085		$	21,460		$	14,193	$	15,296		$	—		$	239,844
	Intersegment revenue	(632		)	(5,245		)	—		(130		)	(180		)	—		(2,155		)	—			(8,342		)
	Revenue from external customers	67,100			52,581			32,252		30,955			21,280			14,193		13,141			—			231,502
	Adjusted EBITDA	46,433			26,839			14,328		15,359			10,998			7,448		4,549			(1,543		)	124,411
	Total assets	1,680,130			711,092			196,964		373,152			207,417			292,518		85,160			505,307			4,051,740
	Capital expenditures, net of stimulus grant reimbursements	19,459			15,911			419		8,388			2,459			16,670		3,350			—			66,656
Reconciliation from net earnings/(loss) to Adjusted EBITDA	'
	Reconciliations from net earnings/(loss) to Adjusted EBITDA by segment and on a consolidated basis are as follows:
	Reconciliation from net earnings/(loss) to Adjusted EBITDA
		Three months ended September 30, 2013
		Dark Fiber			Waves			SONET		Ethernet			IP			MIG		zColo			Corp/			Zayo Group
																					elimination
	Net earnings/(loss)	$	8,579		$	11,550		$	6,998	$	9,493		$	9,393		$	3,154	$	2,717		$	(79,780	)	$	(27,896	)
	Interest expense	20			45			3		5			2			5		413			51,004			51,497
	Provision for income taxes	—			—			—		—			—			—		—			8,534			8,534
	Depreciation and amortization expense	39,914			16,818			5,380		7,356			2,682			5,915		2,510			—			80,575
	Transaction costs	22			23			5		20			8			15		494			—			587
	Stock-based compensation	5,750			4,499			2,587		3,506			2,167			2,388		923			20,864			42,684
	Foreign currency gain on intercompany loans	—			—			—		—			—			—		—			(622		)	(622		)
	Adjusted EBITDA	$	54,285		$	32,935		$	14,973	$	20,380		$	14,252		$	11,477	$	7,057		$	—		$	155,359
		Three months ended September 30, 2012
		Dark Fiber			Waves			SONET		Ethernet			IP			MIG		zColo			Corp/			Zayo Group
																					elimination
	Net earnings/(loss)	$	6,813		$	4,074		$	7,765	$	3,515		$	6,898		$	247	$	743		$	(95,641	)	$	(65,586	)
	Earnings from discontinued operations, net of taxes	—			—			—		—			—			—		—			(1,808		)	(1,808		)
	Interest expense	35			61			11		15			5			11		—			62,417			62,555
	Provision for income taxes	—			—			—		—			—			—		—			(36,588		)	(36,588		)
	Depreciation and amortization expense	35,771			19,310			5,442		9,281			2,689			5,005		2,051			—			79,549
	Transaction costs	2,436			2,240			570		1,980			878			1,682		1,597			—			11,383
	Stock-based compensation	1,378			1,154			540		568			528			503		158			5,652			10,481
	Loss on extinguishment of debt	—			—			—		—			—			—		—			64,975			64,975
	Foreign currency gain on intercompany loans	—			—			—		—			—			—		—			(550		)	(550		)
	Adjusted EBITDA	$	46,433		$	26,839		$	14,328	$	15,359		$	10,998		$	7,448	$	4,549		$	(1,543	)	$	124,411

Condensed_Consolidating_Financ1

Condensed Consolidating Financial Information (Tables)	3 Months Ended
	Sep. 30, 2013
Condensed Consolidating Financial Information [Abstract]	'
Schedule Of Condensed Consolidating Balance Sheet	'
	Condensed Consolidating Balance Sheets (Unaudited)
	September 30, 2013
		Zayo Group,			Guarantor			Non-			Eliminations				Total
		LLC			Subsidiaries			Guarantor
								Subsidiaries
		(Issuer)
	Assets
	Current assets
	Cash and cash equivalents	$	88,146		$	1,013		$	3,274		$	—			$	92,433
	Trade receivables, net	40,920			5,122			16,494			—				62,536
	Due from related parties	533			—			—			—				533
	Prepaid expenses	13,519			2,239			2,915			—				18,673
	Deferred income taxes	30,600			—			—			—				30,600
	Other assets	1,931			6			52			—				1,989
	Total current assets	175,649			8,380			22,735			—				206,764
	Property and equipment, net	2,291,534			61,893			95,337			—				2,448,764
	Intangible assets, net	575,681			18,036			33,477			—				627,194
	Goodwill	620,456			15,058			49,770			—				685,284
	Debt issuance costs, net	95,901			—			—			—				95,901
	Deferred income taxes, net	53,732			—			—			—				53,732
	Other assets	24,305			3,750			805			—				28,860
	Related party receivable, long-term	10,500			—			—			(10,500		)		—
	Investment in subsidiary	231,567			—			—			(231,567		)		—
	Total assets	$	4,079,325		$	107,117		$	202,124		$	(242,067	)		$	4,146,499
	Liabilities and member’s equity
	Current liabilities
	Current portion of long-term debt	$	16,200		$	—		$	—		$	—			$	16,200
	Accounts payable	17,550			923			2,449			—				20,922
	Accrued liabilities	98,246			5,968			8,226			—				112,440
	Accrued interest	26,387			—			—			—				26,387
	Capital lease obligations, current	1,881			5,731			—			—				7,612
	Due to related parties	(2,198		)	—			2,198			—				—
	Deferred revenue, current	51,671			882			2,060			—				54,613
	Total current liabilities	209,737			13,504			14,933			—				238,174
	Long-term debt, non-current	2,811,323			—			—			—				2,811,323
	Related party debt, long-term	—			—			10,500			(10,500		)		—
	Capital lease obligations, non-current	5,865			9,820			—			—				15,685
	Deferred revenue, non-current	327,212			3,920			3,254			—				334,386
	Stock-based compensation liability	195,279			3,703			2,081			—				201,063
	Deferred income taxes, net	—			—			7,374			—				7,374
	Other long-term liabilities	11,190			8,517			68			—				19,775
	Total liabilities	3,560,606			39,464			38,210			(10,500		)		3,627,780
	Member’s equity
	Member’s interest	755,407			33,874			149,999			(231,567		)		707,713
	Accumulated other comprehensive income	—			—			4,704			—				4,704
	(Accumulated deficit)/retained earnings	(236,688		)	33,779			9,211			—				(193,698		)
	Total member’s equity	518,719			67,653			163,914			(231,567		)		518,719
	Total liabilities and member’s equity	$	4,079,325		$	107,117		$	202,124		$	(242,067	)		$	4,146,499
	Condensed Consolidating Balance Sheets (Unaudited)
	June 30, 2013
		Zayo Group,			Guarantor			Non-			Eliminations					Total
		LLC			Subsidiaries			Guarantor
								Subsidiaries
		(Issuer)
	Assets
	Current assets
	Cash and cash equivalents	$	83,608		$	1,009		3,531			$	—				$	88,148
	Trade receivables, net	52,377			4,284			11,150			—					67,811
	Due from related parties	2,113			—			(384		)	(1,107		)			622
	Prepaid expenses	14,768			1,634			2,786			—					19,188
	Deferred income taxes	30,600			—			—			—					30,600
	Restricted cash	—			—			—			—					—
	Other assets, current	2,843			6			2			—					2,851
Total current assets	186,309			6,933			17,085			(1,107		)			209,220
Property and equipment, net	2,274,764			48,673			87,783			—					2,411,220
Intangible assets, net	585,590			18,695			31,973			—					636,258
Goodwill	620,812			15,055			46,908			—					682,775
Debt issuance costs, net	99,098			—			—			—					99,098
Deferred income taxes, net	60,036			—			—			—					60,036
Other assets	25,332			3,130			822			—					29,284
Related party receivable, long-term	10,427			—			—			(10,427		)			—
Investment in subsidiary	216,224			—			—			(216,224		)			—
Total assets	$	4,078,592		$	92,486		184,571			$	(227,758	)			$	4,127,891
Liabilities and member’s equity
Current liabilities
Current portion of long-term debt	$	16,200		$	—		$	—		$	—				$	16,200
Accounts payable	30,319			1,536			1,622			—					33,477
Accrued liabilities	103,780			5,376			6,776			—					115,932
Accrued interest	55,048			—			—			—					55,048
Capital lease obligations, current	1,493			5,107			—			—					6,600
Due to related-parties	25			—			1,082			(1,107		)			—
Deferred revenue, current	33,170			701			2,106			—					35,977
Total current liabilities	240,035			12,720			11,586			(1,107		)			263,234
Long-term debt, non-current	2,814,505			—			—			—					2,814,505
Related party debt, long-term	—			—			10,427			(10,427		)			—
Capital lease obligations, non-current	6,487			80			—			—					6,567
Deferred revenue, non-current	318,188			3,850			4,142			—					326,180
Deferred income taxes, net	—			—			5,560			—			—		5,560
Stock-based compensation liability	154,435			2,794			1,291			—					158,520
Other long-term liabilities	11,511			8,311			70			—					19,892
Total liabilities	3,545,161			27,755			33,076			(11,534		)			3,594,458
Member’s equity
Member’s interest	736,439			33,748			150,000			(216,224		)			703,963
Accumulated other comprehensive loss	—			—			(4,755		)	—					(4,755		)
(Accumulated deficit)/retained earnings	(203,008		)	30,983			6,250			—					(165,775		)
Total member’s equity	533,431			64,731			151,495			(216,224		)			533,433
Total liabilities and member’s equity	$	4,078,592		$	92,486		184,571			$	(227,758	)			$	4,127,891
Schedule Of Condensed Consolidating Statements Of Operations	'
	Condensed Consolidating Statements of Operations (Unaudited)
	For the three months ended September 30, 2013
		Zayo Group,			Guarantor			Non-			Eliminations				Total
		LLC			Subsidiaries			Guarantor
								Subsidiaries
		(Issuer)
	Revenue	$	230,821		$	18,709		$	14,815		$	—			$	264,345
	Operating costs and expenses
	Operating costs, excluding depreciation and amortization	24,880			8,536			1,466			—				34,882
	Selling, general and administrative expenses, excluding stock-based compensation	65,513			3,732			5,487			—				74,732
	Stock-based compensation	41,078			909			697			—				42,684
	Selling, general and administrative expenses	106,591			4,641			6,184			—				117,416
	Depreciation and amortization	74,972			2,325			3,278			—				80,575
	Total operating costs and expenses	206,443			15,502			10,928			—				232,873
	Operating income	24,378			3,207			3,887			—				31,472
	Other expenses
	Interest expense	(51,013		)	(412		)	(72		)	—				(51,497		)
	Other income, net	39			1			623			—				663
	Equity in net earnings of subsidiaries	5,787			—			—			(5,787		)		—
	Total other (expenses)/income, net	(45,187		)	(411		)	551			(5,787		)		(50,834		)
	(Loss)/earnings before provision for income taxes	(20,809		)	2,796			4,438			(5,787		)		(19,362		)
	Provision for income taxes	7,087			—			1,447			—				8,534
	(Loss)/earnings from continuing operations	(27,896		)	2,796			2,991			(5,787		)		(27,896		)
	Earnings from discontinued operations, net of income taxes	—			—			—			—				—
	Net (loss)/earnings	$	(27,896	)	$	2,796		$	2,991		$	(5,787	)		$	(27,896	)
	Condensed Consolidating Statements of Operations (Unaudited)
	For the three months ended September 30, 2012
		Zayo Group,			Guarantor			Non-			Eliminations				Total
		LLC			Subsidiaries			Guarantor
								Subsidiaries
		(Issuer)
	Revenue	$	201,919		$	15,072		$	14,511		$	—			$	231,502
	Operating costs and expenses
	Operating costs, excluding depreciation and amortization	23,115			7,696			1,906			—				32,717
	Selling, general and administrative expenses, excluding stock-based compensation	73,434			4,451			7,907			—				85,792
	Stock-based compensation	10,125			154			202			—				10,481
	Selling, general and administrative expenses	83,559			4,605			8,109			—				96,273
	Depreciation and amortization	74,207			2,049			3,293			—				79,549
	Total operating costs and expenses	180,881			14,350			13,308			—				208,539
	Operating income	21,038			722			1,203			—				22,963
	Other expenses
	Interest expense	(62,443		)	3			(115		)	—				(62,555		)
	Loss on extinguishment of debt	(64,975		)	—			—			—				$	(64,975	)
	Other income, net	35			—			550			—				585
	Equity in net earnings of subsidiaries	1,362			—			—			(1,362		)		—
	Total other expense, net	(126,021		)	3			435			(1,362		)		(126,945		)
	(Loss)/earnings from continuing operations before provision for income taxes	(104,983		)	725			1,638			(1,362		)		(103,982		)
	Provision/(benefit) for income taxes	(37,589		)	—			1,001			—				(36,588		)
	Loss from continuing operations	(67,394		)	725			637			(1,362		)		(67,394		)
	Earnings from discontinued operations, net of income taxes	1,808			—			—			—				1,808
	Net (loss)/earnings	$	(65,586	)	$	725		$	637		$	(1,362	)		$	(65,586	)
Schedule Of Condensed Consolidating Statements Of Cash Flows	'
	Condensed Consolidating Statements of Cash Flows (Unaudited)
	For the three months ended September 30, 2013
		Zayo Group,			Guarantor			Non-			Total
		LLC			Subsidiaries			Guarantor
								Subsidiaries
		(Issuer)
	Net cash provided by operating activities	$	83,383		$	7,521		$	2,973		$	93,877
	Cash flows from investing activities:
	Purchases of property and equipment	(80,520		)	(2,799		)	(3,353		)	(86,672		)
	Acquisitions, net of cash acquired	—			(294		)	—			(294		)
	Net cash used in investing activities	(80,520		)	(3,093		)	(3,353		)	(86,966		)
	Cash flows from financing activities:
	Equity contributions	1,881			—			—			1,881
	Principal repayments on long-term debt	(4,050		)	—			—			(4,050		)
	Principal repayments on capital lease obligations	(251		)	(146		)	—			(397		)
	Debt issuance costs, net of early redemption fees	(183		)	—			—			(183		)
	Net cash provided by/(used in) financing activities	1,675			(4,424		)	—			(2,749		)
	Effect of changes in foreign exchange rates on cash	—			—			123			123
	Net increase/(decrease) in cash and cash equivalents	4,538			4			(257		)	4,285
	Cash and cash equivalents, beginning of period	83,608			1,009			3,531			88,148
	Cash and cash equivalents, end of period	$	88,146		$	1,013		$	3,274		$	92,433
	Condensed Consolidating Statements of Cash Flows (Unaudited)
	For the three months ended September 30, 2012
		Zayo Group,			Guarantor			Non-			Total
		LLC			Subsidiaries			Guarantor
								Subsidiaries
	Net cash provided by/(used in) operating activities	$	71,435		$	5,202		$	2,433		$	79,070
	Cash flows from investing activities:
	Purchases of property and equipment, net of stimulus grants	(61,901		)	(3,253		)	(1,502		)	(66,656		)
	Acquisitions, net of cash acquired	(2,336,057		)	—			7,892			(2,328,165		)
	Net cash used in investing activities	(2,397,958		)	(3,253		)	6,390			(2,394,821		)
	Cash flows from financing activities:
	Equity contributions	337,203			—			—			337,203
	Principal repayments on capital lease obligations	(378		)	—			—			(378		)
	Principal repayments on long-term debt	(697,475		)	—			—			(697,475		)
	Payment of early redemption fees on debt extinguished	(39,797		)	—			—			(39,797		)
	Dividend received/(paid)	636			(636		)	—			—
	Proceeds from borrowings	2,840,000			—			—			2,840,000
	Changes in restricted cash	22,415			—			—			22,415
	Cash contributed to ZPS	(2,424		)	—			—			(2,424		)
	Payment of deferred debt issuance costs	(82,508		)	—			—			(82,508		)
	Net cash provided by/(used in) financing activities	2,377,672			(636		)	—			2,377,036
	Cash flows from discontinued operations
	Cash flows from discontinued operations	1,544			—			—			1,544
	Effect of changes in foreign exchange rates on cash	—			—			208			208
	Net increase in cash and cash equivalents	52,692			1,313			9,032			63,037
	Cash and cash equivalents, beginning of period	149,574			1,119			—			150,693
	Cash and cash equivalents, end of period	$	202,266		$	2,432		$	9,032		$	213,730

Acquisitions_Narrative_Details

Acquisitions (Narrative) (Details) (USD $)

3 Months Ended

12 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Jun. 30, 2013

Jul. 02, 2012

Aug. 01, 2013

Sep. 30, 2013

Sep. 30, 2012

Dec. 14, 2012

Dec. 14, 2012

31-May-13

Oct. 02, 2013

Aug. 13, 2013

Oct. 02, 2013

Revolving Credit Facility [Member]

Colocation Asset Purchase [Member]

Colocation Asset Purchase [Member]

Colocation Asset Purchase [Member]

First Telecom [Member]

First Telecom [Member]

Core NAP [Member]

Access [Member]

Access [Member]

Subsequent Event [Member]

Customer relationships [Member]

Fiberlink [Member]

Business Acquisition [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

Number of business combinations

26

'

6

'

'

'

'

'

'

'

'

'

'

Acquisition date

'

'

'

'

1-Aug-13

'

'

14-Dec-12

'

31-May-13

1-Oct-13

'

'

Business acquisition purchase price

'

'

'

'

$1,932,000

'

'

'

'

'

'

'

'

Number of shares issued for acquisition

'

'

'

'

301,949

'

'

'

'

'

'

'

'

Fair value of shares issued for acquisition

'

'

'

'

1,637,000

'

'

'

'

'

'

'

'

Cash consideration

'

'

'

'

344,000

'

'

'

'

'

'

'

'

Cash consideration, net of cash acquired

294,000

2,328,165,000

2,485,809,000

'

294,000

294,000

0

109,700,000

'

7,030,000

'

'

'

Purchase price, held in escrow

'

'

'

'

278,000

'

'

11,000,000

'

1,095,000

'

'

'

Purchase price held in escrow, shares

'

'

'

'

51,310

'

'

'

'

'

'

'

'

Acquisition agreement date

'

'

'

'

'

'

'

'

'

31-May-13

'

13-Aug-13

2-Oct-13

Percentage of company acquired

'

'

'

'

'

'

'

100.00%

'

'

100.00%

'

100.00%

Estimated useful life of acquired customer relationships

'

'

'

'

'

'

'

'

'18 years

'

'

'

'

Acquisition-related costs

587,000

11,383,000

'

'

'

'

'

'

'

'

'

'

'

Preliminary purchase price

'

'

'

'

'

'

'

'

'

'

40,068,000

'

43,000,000

Notes face amount

'

'

'

$250,000,000

'

'

'

'

'

'

'

'

'

Acquisitions_Schedule_Of_Acqui

Acquisitions (Schedule Of Acquisition) (Details) (USD $)	3 Months Ended		12 Months Ended	0 Months Ended			3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2013	Dec. 14, 2012	31-May-13	Aug. 01, 2013	Sep. 30, 2013	Sep. 30, 2012
				First Telecom [Member]	Core NAP [Member]	Colocation Asset Purchase [Member]	Colocation Asset Purchase [Member]	Colocation Asset Purchase [Member]
Business Acquisition [Line Items]	'	'	'	'	'	'	'	'
Acquisition date	'	'	'	14-Dec-12	31-May-13	1-Aug-13	'	'
Cash	'	'	'	$0	($50)	($50)	'	'
Other current assets	'	'	'	5,945	175	619	'	'
Property and equipment	'	'	'	37,919	1,672	8,993	'	'
Deferred tax assets, net	'	'	'	11,964	0	0	'	'
Intangibles	'	'	'	35,516	0	0	'	'
Goodwill	685,284	'	682,775	44,580	5,674	0	'	'
Other assets	'	'	'	157	21	545	'	'
Total assets acquired	'	'	'	136,081	7,592	10,207	'	'
Current liabilities	'	'	'	4,560	279	719	'	'
Deferred revenue	'	'	'	21,821	0	219	'	'
Other liabilities	'	'	'	0	233	7,287	'	'
Total liabilities assumed	'	'	'	26,381	512	8,225	'	'
Net assets acquired	'	'	'	109,700	7,080	1,982	'	'
Net cash paid	$294	$2,328,165	$2,485,809	$109,700	$7,030	$294	$294	$0

Acquisitions_Schedule_Of_ProFo

Acquisitions (Schedule Of Pro-Forma Financial Information) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Business Combinations [Abstract]	'	'
Revenue	$267,865	$255,636
Loss from continuing operations	($27,232)	($57,697)

SpinOff_Of_Business_Details

Spin-Off Of Business (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Discontinued Operations and Disposal Groups [Abstract]	'	'
Revenues	$0	$6,474
Earnings before income taxes	0	3,011
Income tax expense	0	1,203
Earnings from discontinued operations, net of income taxes	0	1,808
Discontinued operations, intercompany expenses	'	$1,544

Goodwill_Narrative_Details

Goodwill (Narrative) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013
Goodwill and Intangible Assets Disclosure [Abstract]	'	'
Goodwill	$685,284	$682,775
Foreign currency translation	2,865	'
Decrease to goodwill acquired	$356	'

Goodwill_Schedule_Of_Goodwill_

Goodwill (Schedule Of Goodwill) (Details) (USD $)

3 Months Ended

3 Months Ended

3 Months Ended

In Thousands, unless otherwise specified

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Dec. 14, 2012

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

31-May-13

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Waves [Member]

Sonet [Member]

Ethernet [Member]

IP [Member]

MIG [Member]

Dark Fiber [Member]

zColo [Member]

First Telecom [Member]

First Telecom [Member]

First Telecom [Member]

First Telecom [Member]

First Telecom [Member]

First Telecom [Member]

First Telecom [Member]

First Telecom [Member]

First Telecom [Member]

Core NAP [Member]

Core NAP [Member]

Core NAP [Member]

Core NAP [Member]

Core NAP [Member]

Core NAP [Member]

Core NAP [Member]

Core NAP [Member]

Core NAP [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Purchase accounting adjustments [Member]

Waves [Member]

Sonet [Member]

Ethernet [Member]

IP [Member]

MIG [Member]

Dark Fiber [Member]

zColo [Member]

Waves [Member]

Sonet [Member]

Ethernet [Member]

IP [Member]

MIG [Member]

Dark Fiber [Member]

zColo [Member]

Goodwill, beginning Balance

$682,775

$215,864

$50,286

$91,708

$80,072

$38,313

$189,869

$16,663

$44,580

'

'

'

'

'

'

'

'

$5,674

'

'

'

'

'

'

'

'

Additions

'

'

'

'

'

'

'

'

'

-358

0

0

0

0

0

-358

0

'

2

0

0

0

0

0

0

2

Foreign currency translation

2,865

297

0

81

115

0

2,273

99

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Goodwill, ending balance

$685,284

$216,161

$50,286

$91,789

$80,187

$38,313

$191,784

$16,764

$44,580

'

'

'

'

'

'

'

'

$5,674

'

'

'

'

'

'

'

'

Intangible_Assets_Schedule_Of_

Intangible Assets (Schedule Of Intangible Assets) (Details) (USD $)	Sep. 30, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Finite-Lived Intangible Assets [Line Items]	'	'
Finite-Lived Intangible Assets, Gross	$717,219	$717,984
Accumulated Amortization	-93,513	-85,214
Finite-Lived Intangible Assets, Net	623,706	632,770
Total Gross Carrying Amount	720,707	721,472
Intangible assets, net	627,194	636,258
Customer relationships [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Finite-Lived Intangible Assets, Gross	714,965	715,730
Accumulated Amortization	-92,709	-84,570
Finite-Lived Intangible Assets, Net	622,256	631,160
Tradenames [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Finite-Lived Intangible Assets, Gross	1,179	1,179
Accumulated Amortization	-737	-590
Finite-Lived Intangible Assets, Net	442	589
Underlying rights [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Finite-Lived Intangible Assets, Gross	1,075	1,075
Accumulated Amortization	-67	-54
Finite-Lived Intangible Assets, Net	1,008	1,021
Certifications [Member]	'	'
Finite-Lived Intangible Assets [Line Items]	'	'
Indefinite-Lived Intangible Assets	$3,488	$3,488

LongTerm_Debt_Narrative_Detail

Long-Term Debt (Narrative) (Details) (USD $)

3 Months Ended

12 Months Ended

0 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

3 Months Ended

0 Months Ended

3 Months Ended

3 Months Ended

0 Months Ended

3 Months Ended

Sep. 30, 2013

Sep. 30, 2012

Jun. 30, 2013

Oct. 05, 2012

Oct. 05, 2012

Jul. 02, 2012

Sep. 30, 2013

Jul. 02, 2012

Sep. 30, 2013

Sep. 30, 2013

Jun. 30, 2013

Jul. 02, 2012

Oct. 05, 2012

Oct. 05, 2012

Sep. 30, 2013

Jun. 30, 2013

Jul. 02, 2012

Oct. 05, 2012

Sep. 30, 2013

Jun. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Aug. 13, 2012

Sep. 30, 2013

Sep. 30, 2012

Jun. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Oct. 05, 2012

Sep. 30, 2013

Sep. 30, 2013

Term Loan [Member]

Term Loan [Member]

Senior Secured Notes [Member]

Senior Secured Notes [Member]

Senior Unsecured Notes [Member]

Senior Unsecured Notes [Member]

Revolver [Member]

Revolver [Member]

Revolver [Member]

Revolver [Member]

Revolver [Member]

Term Loan [Member]

Term Loan [Member]

Term Loan [Member]

Term Loan [Member]

Notes [Member]

Notes [Member]

Standby Letter Of Credit [Member]

Standby Letter Of Credit [Member]

Standby Letter Of Credit [Member]

Interest Rate Swap [Member]

Interest Rate Swap [Member]

Interest Rate Swap [Member]

Interest Rate Swap [Member]

LIBOR [Member]

LIBOR [Member]

LIBOR [Member]

LIBOR [Member]

Debt Instrument, Redemption, Period One [Member]

Debt Instrument, Redemption, Period One [Member]

Fourth Amendment [Member]

Fourth Amendment [Member]

Second Amendment [Member]

Fourth Amendment [Member]

Second Amendment [Member]

Minimum [Member]

Maximum [Member]

Revolver [Member]

Term Loan [Member]

Term Loan [Member]

Term Loan [Member]

Senior Secured Notes [Member]

Senior Unsecured Notes [Member]

Minimum [Member]

Fourth Amendment [Member]

Minimum [Member]

Second Amendment [Member]

Debt Instrument [Line Items]

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Ownership percentage in subsidiary

100.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Notes face amount

'

'

'

'

'

$750,000,000

'

$500,000,000

'

'

'

$250,000,000

'

'

'

'

$1,620,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument, interest rate

'

'

'

'

'

8.13%

'

10.13%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument, maturity date

'

'

'

'

'

'2020

'

'2020

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Discount on debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Effective interest rate

'

'

'

'

'

'

'

'

'

3.25%

3.27%

'

'

'

4.50%

4.50%

7.13%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage over variable rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

3.00%

3.50%

1.00%

4.00%

'

'

Interest rate decrease

'

'

'

0.50%

0.25%

'

'

'

'

'

'

'

187.50%

0.50%

'

'

'

187.50%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Floor rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.25%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt instrument carrying amount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,580,705,000

'

'

'

1,250,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

Net premium/discount

'

'

'

'

'

'

'

'

'

'

'

'

'

'

22,227,000

23,094,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Line of credit outstanding

'

'

'

'

'

'

'

'

'

'

0

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unused commitment, percentage

'

'

'

'

'

'

'

'

'

0.50%

'

'

'

'

'

'

'

'

'

'

0.25%

'

'

'

'

'

'

'

'

'

'

'

'

Payment towards principal

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4,050,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of excess cash flows committed to debt payments

'

'

'

'

'

'

'

'

'

'

'

'

'

'

50.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Long-term Debt

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1,577,523,000

'

'

'

1,250,000,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Outstanding letters of credit

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

6,561,000

'

'

'

'

'

'

'

'

'

'

'

'

Available borrowing capacity

'

'

'

'

'

'

'

'

'

243,439,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest rate during period

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2.00%

3.00%

'

'

'

'

'

'

'

'

'

'

Secured Debt Ratio

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

4.5

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Total Leverage Ratio

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

5.25

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Redemption price

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

100.00%

100.00%

Percentage of aggregate debt instruments outstanding subject to redemption

35.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Mandatory redemption price expressed as percentage of principal amount on senior notes in event of an equity offering

'

'

'

'

'

'

108.13%

'

110.25%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Percentage of remaining outstanding aggregate principal amount of notes issued under the indenture

65.00%

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Equity offering redemption period

'90 days

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Debt issuance cost

'

'

116,293,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Unamortized debt issuance cost

95,901,000

'

98,960,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Accretion of premium on debt

14,863,000

'

11,482,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Interest expense associated with the amortization of debt issuance costs

3,381,000

3,003,000

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

Notional amount of derivative

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

750,000,000

'

'

'

'

'

'

'

'

'

Derivative, maturity date

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

30-Jun-17

'

'

'

'

'

'

'

'

'

Derivative, fixed interest rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.67%

'

'

'

'

'

'

'

'

'

Derivative, floor rate

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

1.25%

'

'

'

'

'

'

'

'

'

Change in fair value of interest rate swap

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

2,264,000

4,484,000

'

'

'

'

'

'

'

Interest Rate Derivative Assets, at Fair Value

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

'

$378,000

'

$2,642,000

'

'

'

'

'

'

LongTerm_Debt_Debt_Covenants_D

Long-Term Debt (Debt Covenants) (Details)	Sep. 30, 2013
Fiscal Quarter Ending September 30, 2013 [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	1.75
Fiscal Quarter Ending December 31, 2013 [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	1.75
Fiscal Quarter Ending March 31, 2014 [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	1.75
Fiscal Quarter Ending June 30, 2014 [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	1.75
Fiscal Quarter Ending September 30, 2014 [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	2
Fiscal Quarter Ending December 31, 2014 [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	2
Fiscal Quarter Ending March 31, 2015 [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	2
Fiscal Quarter Ending June 30, 2015 [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	2.25
Fiscal Quarter Ending September 30, 2015 [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	2.25
Fiscal Quarter Ending December 30, 2015 [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	2.25
Fiscal Quarter Ending March 31, 2016 [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	2.5
Fiscal Quarter Ending June 30, 2016 [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	2.5
Fiscal Quarter Ending September 30, 2016 [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	2.5
Fiscal Quarter Ending December 31, 2016 and thereafter [Member]	'
Schedule of Debt Covenants [Line Items]	'
Fixed-Charge Coverage Ratio	2.75

LongTerm_Debt_Redemption_Right

Long-Term Debt (Redemption Rights) (Details)	3 Months Ended
	Sep. 30, 2013
Debt Instrument, Redemption, Period One [Member] | Senior Secured Notes [Member]	'
Debt Instrument [Line Items]	'
Redemption price	100.00%
Debt Instrument, Redemption, Period One [Member] | Senior Unsecured Notes [Member]	'
Debt Instrument [Line Items]	'
Redemption price	100.00%
Debt Instrument, Redemption, Period Two [Member] | Senior Secured Notes [Member]	'
Debt Instrument [Line Items]	'
Redemption price	104.06%
Debt Instrument, Redemption, Period Two [Member] | Senior Unsecured Notes [Member]	'
Debt Instrument [Line Items]	'
Redemption price	105.06%
Debt Instrument, Redemption, Period Three [Member] | Senior Secured Notes [Member]	'
Debt Instrument [Line Items]	'
Redemption price	102.03%
Debt Instrument, Redemption, Period Three [Member] | Senior Unsecured Notes [Member]	'
Debt Instrument [Line Items]	'
Redemption price	102.53%
Debt Instrument, Redemption, Period Four [Member] | Senior Secured Notes [Member]	'
Debt Instrument [Line Items]	'
Redemption price	100.00%
Debt Instrument, Redemption, Period Four [Member] | Senior Unsecured Notes [Member]	'
Debt Instrument [Line Items]	'
Redemption price	100.00%

Income_Taxes_Schedule_Of_Recon

Income Taxes (Schedule Of Reconciliation Of Income Tax Provision) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012
Income Tax Disclosure [Abstract]	'	'	'	'	'
Expected (benefit)/provision at statutory rate	($6,779)	'	'	'	($36,391)
Non-deductible stock-based compensation	14,939	'	'	'	3,668
State income taxes provision/(benefit), net of federal benefit	783	'	'	'	-4,639
Transactions costs not deductible for tax purposes	192	'	'	'	910
Foreign tax rate differential	-666	'	'	'	-459
Other, net	65	'	'	'	323
Provision/(benefit) for income taxes	$8,534	$9,460	$6,519	($3,438)	($36,588)

Income_Taxes_Schedule_of_Inter

Income Taxes (Schedule of Interim Prior Period Adjustments) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012
Provision/(benefit) for income taxes	$8,534	$9,460	$6,519	($3,438)	($36,588)
Net loss	-27,896	-24,386	-18,543	-34,241	-65,586
As originally stated [Member]	'	'	'	'	'
Provision/(benefit) for income taxes	'	-16,056	13,305	6,025	-27,320
Net loss	'	1,130	-25,329	-43,704	-74,854
AboveNet [Member] | Fair value adjustments [Member]	'	'	'	'	'
Provision/(benefit) for income taxes	'	25,516	-6,786	-9,463	-9,268
Net loss	'	($25,516)	$6,786	$9,463	$9,268

Equity_Details

Equity (Details) (USD $)	3 Months Ended		0 Months Ended
In Thousands, except Share data, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2013	Aug. 01, 2013
		CII [Member]	Colocation Asset Purchase [Member]
Deferred Compensation Arrangement with Individual, Excluding Share-based Payments and Postretirement Benefits [Line Items]	'	'	'
Cash contributed to the Company	$1,881	$1,881	'
Number of shares issued for acquisition	'	'	301,949
Fair value of shares issued for acquisition	'	'	1,637
Purchase price, held in escrow	'	'	$278
Purchase price held in escrow, shares	'	'	51,310

StockBased_Compensation_Narrat

Stock-Based Compensation (Narrative) (Details) (USD $)

3 Months Ended

12 Months Ended

12 Months Ended

3 Months Ended

12 Months Ended

In Thousands, except Share data, unless otherwise specified

Sep. 30, 2013

Sep. 30, 2012

Jun. 30, 2013

Jun. 30, 2013

Sep. 30, 2013

Jun. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2013

Sep. 30, 2012

Sep. 30, 2013

Jun. 30, 2013

Jun. 30, 2013

Jun. 30, 2013

Jun. 30, 2013

CII [Member]

CII [Member]

Maximum [Member]

Class H [Member]

Class I [Member]

Common Units [Member]

Common Units [Member]

Preferred Unit Holders [Member]

Preferred Unit Holders [Member]

Preferred Unit Holders [Member]

Preferred Unit Holders [Member]

Common Unit Holders [Member]

CII [Member]

CII [Member]

Minimum [Member]

Maximum [Member]

Minimum [Member]

Shares authorized

'

'

'

'

525,000,000

'

'

'

'

'

'

'

'

'

'

Common units issued

'

'

'

'

'

'

598,822

45,767,059

'

'

70,193,000

'

'

'

'

Common units outstanding

'

'

'

'

511,590,542

'

'

'

'

'

'

'

'

'

'

Remaining common units available for issue

'

'

'

'

13,409,458

'

'

'

'

'

'

'

'

'

'

Stock-based compensation liability

$201,063

'

$158,520

'

'

'

'

'

'

'

'

'

'

'

'

Fair value of unvested common units

'

'

'

'

'

'

'

'

139,582

'

'

'

'

'

'

Common unit vesting period

'

'

'

'

'

'

'

'

'3 years

'

'

'

'

'

'

Stock-based compensation expense

42,684

10,481

'

'

'

'

'

'

42,452

10,267

380

'

'

'

'

Reimbursement Return

'

'

'

'

'

'

'

'

'

'

'

6.00%

'

'

'

Proceeds from a liquidation event

'

'

'

'

'

20.00%

'

'

'

'

'

'

80.00%

85.00%

15.00%

Maximum incremental allocation of proceeds from a liquidation event

'

'

'

20.00%

'

'

'

'

'

'

'

'

'

'

'

Minimum multiple realized

'

'

'

'

'

'

'

'

'

'

'

3.5

'

'

'

Stock-based compensation related increase to member's interest

$232

$214

'

'

'

'

'

'

'

'

'

'

'

'

'

StockBased_Compensation_Schedu

Stock-Based Compensation (Schedule of Estimated Fair Value of Common Units) (Details) (USD $)	Sep. 30, 2013	Jun. 30, 2013
Class A [Member]	'	'
Estimated Fair Value Of Common Unit Class	$1.63	$1.50
Class B [Member]	'	'
Estimated Fair Value Of Common Unit Class	$1.46	$1.34
Class C [Member]	'	'
Estimated Fair Value Of Common Unit Class	$1.25	$1.14
Class D [Member]	'	'
Estimated Fair Value Of Common Unit Class	$1.21	$1.10
Class E [Member]	'	'
Estimated Fair Value Of Common Unit Class	$1.04	$0.95
Class F [Member]	'	'
Estimated Fair Value Of Common Unit Class	$0.93	$0.75
Class G [Member]	'	'
Estimated Fair Value Of Common Unit Class	$0.51	$0.46
Class H [Member]	'	'
Estimated Fair Value Of Common Unit Class	$0.43	$0.38
Class I [Member]	'	'
Estimated Fair Value Of Common Unit Class	$0.27	$0

StockBased_Compensation_Schedu1

Stock-Based Compensation (Schedule of Liquidation Thresholds) (Details) (CII [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013
Class A [Member]	'
Liquidation distribution to previous unit holders required to share in liquidation distribution	$0
Class B [Member]	'
Liquidation distribution to previous unit holders required to share in liquidation distribution	15,000
Class C [Member]	'
Liquidation distribution to previous unit holders required to share in liquidation distribution	40,000
Class D [Member]	'
Liquidation distribution to previous unit holders required to share in liquidation distribution	45,000
Class E [Member]	'
Liquidation distribution to previous unit holders required to share in liquidation distribution	75,000
Class F [Member]	'
Liquidation distribution to previous unit holders required to share in liquidation distribution	95,000
Class G [Member]	'
Liquidation distribution to previous unit holders required to share in liquidation distribution	235,000
Class H [Member]	'
Liquidation distribution to previous unit holders required to share in liquidation distribution	290,000
Class I [Member]	'
Liquidation distribution to previous unit holders required to share in liquidation distribution	$435,000

Fair_Value_Measurements_Narrat

Fair Value Measurements (Narrative) (Details) (USD $)	3 Months Ended				3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2013	Jun. 30, 2013
	Interest Rate Swap [Member]	Interest Rate Swap [Member]	New Notes [Member]	New Notes [Member]	Term Loan [Member]	Term Loan [Member]
Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]	'	'	'	'	'	'
Carrying value of the notes	'	'	$1,250,000	$1,250,000	$1,577,523	$1,580,705
Fair value of the notes	'	'	1,319,675	1,364,375	'	'
Floor rate	'	'	'	'	1.00%	'
Percentage over variable rate	'	'	'	'	3.50%	'
Hypothetical interest rate increase	10000.00%	'	'	'	1.00%	'
Hypothetical annual interest expense	22,050	'	'	'	15,998	'
Change in fair value of interest rate swap	$2,264	$4,484	'	'	'	'

Fair_Value_Measurements_Schedu

Fair Value Measurements (Schedule Of Financial Instruments Measured At Fair Value On A Recurring Basis) (Details) (USD $)	Sep. 30, 2013	Jun. 30, 2013
In Thousands, unless otherwise specified
Level 2	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Interest Rate Derivative Assets, at Fair Value	$378	$2,642
Level 3	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Stock-based compensation liability	$201,063	$158,520

Commitments_And_Contingencies_

Commitments And Contingencies (Narrative) (Details) (USD $)	Sep. 30, 2013
In Thousands, unless otherwise specified
Commitments and Contingencies Disclosure [Abstract]	'
Purchase commitments	$93,391

Related_Party_Transactions_Nar

Related Party Transactions (Narrative) (Details) (USD $)	Sep. 30, 2013	Jun. 30, 2013	Jul. 02, 2012	Sep. 30, 2013	Jul. 02, 2012
In Thousands, unless otherwise specified			Senior Unsecured Notes [Member]	Zayo Professional Services [Member]	Matthew Erickson [Member]
Related Party Transaction [Line Items]	'	'	'	'	'
Due from related parties	$533	$622	'	'	'
Net working capital surplus	'	'	'	10,447	'
Purchase price of notes	'	'	'	'	$600
Debt instrument, interest rate	'	'	10.13%	'	'
Debt instrument, maturity date	'	'	'2020	'	'

Related_Party_Transactions_Sch

Related Party Transactions (Schedule Of Transactions Recognized With Related-Parties) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012
Related Party Transaction, Due from (to) Related Party [Abstract]	'	'
Revenue	$3,052	$1,699
Operating costs	-125	-166
Selling, general and administrative expenses	-241	-160
Net	$2,686	$1,373

Segment_Reporting_Segment_Repo

Segment Reporting Segment Reporting (Narrative) (Details)	3 Months Ended	6 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
	segments	segments
Segment Reporting [Abstract]	'	'
Number of operating segments	7	3

Segment_Reporting_Summary_Of_S

Segment Reporting (Summary Of Significant Financial Information) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012
Segment Reporting Information [Line Items]	'	'	'	'	'
Gross revenue	$271,596	'	'	'	$239,844
Revenue	264,345	'	'	'	231,502
Adjusted EBITDA	155,359	'	'	'	124,411
Total assets	4,146,499	4,127,891	'	'	4,051,740
Capital expenditures, net of stimulus grant reimbursements	86,672	'	'	'	66,656
Reconciliations from Net Earnings/(Loss) to Adjusted EBITDA [Abstract]	'	'	'	'	'
Net loss	-27,896	-24,386	-18,543	-34,241	-65,586
Earnings from discontinued operations, net of income taxes	0	'	'	'	-1,808
Interest expense	51,497	'	'	'	62,555
(Benefit)/provision for income taxes	8,534	9,460	6,519	-3,438	-36,588
Depreciation and amortization expense	80,575	'	'	'	79,549
Transaction costs	587	'	'	'	11,383
Stock-based compensation	42,684	'	'	'	10,481
Loss on extinguishment of debt	0	'	'	'	64,975
Foreign currency gain on intercompany loans	-622	'	'	'	-550
Adjusted EBITDA	155,359	'	'	'	124,411
Waves [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Gross revenue	63,273	'	'	'	57,826
Revenue	58,472	'	'	'	52,581
Adjusted EBITDA	32,935	'	'	'	26,839
Total assets	804,643	'	'	'	711,092
Capital expenditures, net of stimulus grant reimbursements	22,063	'	'	'	15,911
Reconciliations from Net Earnings/(Loss) to Adjusted EBITDA [Abstract]	'	'	'	'	'
Net loss	11,550	'	'	'	4,074
Earnings from discontinued operations, net of income taxes	'	'	'	'	0
Interest expense	45	'	'	'	61
(Benefit)/provision for income taxes	0	'	'	'	0
Depreciation and amortization expense	16,818	'	'	'	19,310
Transaction costs	23	'	'	'	2,240
Stock-based compensation	4,499	'	'	'	1,154
Loss on extinguishment of debt	'	'	'	'	0
Foreign currency gain on intercompany loans	0	'	'	'	0
Adjusted EBITDA	32,935	'	'	'	26,839
Sonet [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Gross revenue	31,612	'	'	'	32,252
Revenue	31,612	'	'	'	32,252
Adjusted EBITDA	14,973	'	'	'	14,328
Total assets	195,227	'	'	'	196,964
Capital expenditures, net of stimulus grant reimbursements	935	'	'	'	419
Reconciliations from Net Earnings/(Loss) to Adjusted EBITDA [Abstract]	'	'	'	'	'
Net loss	6,998	'	'	'	7,765
Earnings from discontinued operations, net of income taxes	'	'	'	'	0
Interest expense	3	'	'	'	11
(Benefit)/provision for income taxes	0	'	'	'	0
Depreciation and amortization expense	5,380	'	'	'	5,442
Transaction costs	5	'	'	'	570
Stock-based compensation	2,587	'	'	'	540
Loss on extinguishment of debt	'	'	'	'	0
Foreign currency gain on intercompany loans	0	'	'	'	0
Adjusted EBITDA	14,973	'	'	'	14,328
Ethernet [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Gross revenue	36,143	'	'	'	31,085
Revenue	36,129	'	'	'	30,955
Adjusted EBITDA	20,380	'	'	'	15,359
Total assets	410,476	'	'	'	373,152
Capital expenditures, net of stimulus grant reimbursements	13,127	'	'	'	8,388
Reconciliations from Net Earnings/(Loss) to Adjusted EBITDA [Abstract]	'	'	'	'	'
Net loss	9,493	'	'	'	3,515
Earnings from discontinued operations, net of income taxes	'	'	'	'	0
Interest expense	5	'	'	'	15
(Benefit)/provision for income taxes	0	'	'	'	0
Depreciation and amortization expense	7,356	'	'	'	9,281
Transaction costs	20	'	'	'	1,980
Stock-based compensation	3,506	'	'	'	568
Loss on extinguishment of debt	'	'	'	'	0
Foreign currency gain on intercompany loans	0	'	'	'	0
Adjusted EBITDA	20,380	'	'	'	15,359
IP [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Gross revenue	23,829	'	'	'	21,460
Revenue	23,813	'	'	'	21,280
Adjusted EBITDA	14,252	'	'	'	10,998
Total assets	236,958	'	'	'	207,417
Capital expenditures, net of stimulus grant reimbursements	5,361	'	'	'	2,459
Reconciliations from Net Earnings/(Loss) to Adjusted EBITDA [Abstract]	'	'	'	'	'
Net loss	9,393	'	'	'	6,898
Earnings from discontinued operations, net of income taxes	'	'	'	'	0
Interest expense	2	'	'	'	5
(Benefit)/provision for income taxes	0	'	'	'	0
Depreciation and amortization expense	2,682	'	'	'	2,689
Transaction costs	8	'	'	'	878
Stock-based compensation	2,167	'	'	'	528
Loss on extinguishment of debt	'	'	'	'	0
Foreign currency gain on intercompany loans	0	'	'	'	0
Adjusted EBITDA	14,252	'	'	'	10,998
MIG [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Gross revenue	18,945	'	'	'	14,193
Revenue	18,945	'	'	'	14,193
Adjusted EBITDA	11,477	'	'	'	7,448
Total assets	333,841	'	'	'	292,518
Capital expenditures, net of stimulus grant reimbursements	19,169	'	'	'	16,670
Reconciliations from Net Earnings/(Loss) to Adjusted EBITDA [Abstract]	'	'	'	'	'
Net loss	3,154	'	'	'	247
Earnings from discontinued operations, net of income taxes	'	'	'	'	0
Interest expense	5	'	'	'	11
(Benefit)/provision for income taxes	0	'	'	'	0
Depreciation and amortization expense	5,915	'	'	'	5,005
Transaction costs	15	'	'	'	1,682
Stock-based compensation	2,388	'	'	'	503
Loss on extinguishment of debt	'	'	'	'	0
Foreign currency gain on intercompany loans	0	'	'	'	0
Adjusted EBITDA	11,477	'	'	'	7,448
zColo [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Gross revenue	18,935	'	'	'	15,296
Revenue	16,526	'	'	'	13,141
Adjusted EBITDA	7,057	'	'	'	4,549
Total assets	111,137	'	'	'	85,160
Capital expenditures, net of stimulus grant reimbursements	2,799	'	'	'	3,350
Reconciliations from Net Earnings/(Loss) to Adjusted EBITDA [Abstract]	'	'	'	'	'
Net loss	2,717	'	'	'	743
Earnings from discontinued operations, net of income taxes	'	'	'	'	0
Interest expense	413	'	'	'	0
(Benefit)/provision for income taxes	0	'	'	'	0
Depreciation and amortization expense	2,510	'	'	'	2,051
Transaction costs	494	'	'	'	1,597
Stock-based compensation	923	'	'	'	158
Loss on extinguishment of debt	'	'	'	'	0
Foreign currency gain on intercompany loans	0	'	'	'	0
Adjusted EBITDA	7,057	'	'	'	4,549
Dark Fiber [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Gross revenue	78,859	'	'	'	67,732
Revenue	78,848	'	'	'	67,100
Adjusted EBITDA	54,285	'	'	'	46,433
Total assets	1,818,043	'	'	'	1,680,130
Capital expenditures, net of stimulus grant reimbursements	23,218	'	'	'	19,459
Reconciliations from Net Earnings/(Loss) to Adjusted EBITDA [Abstract]	'	'	'	'	'
Net loss	8,579	'	'	'	6,813
Earnings from discontinued operations, net of income taxes	'	'	'	'	0
Interest expense	20	'	'	'	35
(Benefit)/provision for income taxes	0	'	'	'	0
Depreciation and amortization expense	39,914	'	'	'	35,771
Transaction costs	22	'	'	'	2,436
Stock-based compensation	5,750	'	'	'	1,378
Loss on extinguishment of debt	'	'	'	'	0
Foreign currency gain on intercompany loans	0	'	'	'	0
Adjusted EBITDA	54,285	'	'	'	46,433
Corporate [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Gross revenue	0	'	'	'	0
Revenue	0	'	'	'	0
Adjusted EBITDA	0	'	'	'	-1,543
Total assets	236,174	'	'	'	505,307
Capital expenditures, net of stimulus grant reimbursements	0	'	'	'	0
Reconciliations from Net Earnings/(Loss) to Adjusted EBITDA [Abstract]	'	'	'	'	'
Net loss	-79,780	'	'	'	-95,641
Earnings from discontinued operations, net of income taxes	'	'	'	'	-1,808
Interest expense	51,004	'	'	'	62,417
(Benefit)/provision for income taxes	8,534	'	'	'	-36,588
Depreciation and amortization expense	0	'	'	'	0
Transaction costs	0	'	'	'	0
Stock-based compensation	20,864	'	'	'	5,652
Loss on extinguishment of debt	'	'	'	'	64,975
Foreign currency gain on intercompany loans	-622	'	'	'	-550
Adjusted EBITDA	0	'	'	'	-1,543
Intersegment Eliminations [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Revenue	7,251	'	'	'	8,342
Intersegment Eliminations [Member] | Waves [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Revenue	4,801	'	'	'	5,245
Intersegment Eliminations [Member] | Sonet [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Revenue	0	'	'	'	0
Intersegment Eliminations [Member] | Ethernet [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Revenue	14	'	'	'	130
Intersegment Eliminations [Member] | IP [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Revenue	16	'	'	'	180
Intersegment Eliminations [Member] | MIG [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Revenue	0	'	'	'	0
Intersegment Eliminations [Member] | zColo [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Revenue	2,409	'	'	'	2,155
Intersegment Eliminations [Member] | Dark Fiber [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Revenue	11	'	'	'	632
Intersegment Eliminations [Member] | Corporate [Member]	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'
Revenue	'	'	'	'	$0

Condensed_Consolidating_Financ2

Condensed Consolidating Financial Information (Narrative) (Details) (USD $)	3 Months Ended
	Sep. 30, 2013	Sep. 30, 2013	Jul. 02, 2012	Jul. 02, 2012
		Zayo Capital Inc [Member]	Senior Secured Notes [Member]	Senior Unsecured Notes [Member]
Condensed Consolidating Financial Information [Line Items]	'	'	'	'
Ownership percentage in subsidiary	100.00%	100.00%	'	'
Notes face amount	'	'	$750,000,000	$500,000,000

Condensed_Consolidating_Financ3

Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Balance Sheet) (Details) (USD $)	Sep. 30, 2013	Jun. 30, 2013	Sep. 30, 2012	Jun. 30, 2012
In Thousands, unless otherwise specified
Cash and cash equivalents	$92,433	$88,148	$213,730	$150,693
Trade receivables, net	62,536	67,811	'	'
Due from related parties	533	622	'	'
Prepaid expenses	18,673	19,188	'	'
Deferred income taxes	30,600	30,600	'	'
Restricted cash	'	0	'	'
Other assets, current	1,989	2,851	'	'
Total current assets	206,764	209,220	'	'
Property and equipment, net	2,448,764	2,411,220	'	'
Intangible assets, net	627,194	636,258	'	'
Goodwill	685,284	682,775	'	'
Debt issuance costs, net	95,901	99,098	'	'
Deferred income taxes, net	53,732	60,036	'	'
Other assets, non-current	28,860	29,284	'	'
Related party receivable, long-term	0	0	'	'
Investment in subsidiary	0	0	'	'
Total assets	4,146,499	4,127,891	4,051,740	'
Current portion of long-term debt	16,200	16,200	'	'
Accounts payable	20,922	33,477	'	'
Accrued liabilities	112,440	115,932	'	'
Accrued interest	26,387	55,048	'	'
Capital lease obligations, current	7,612	6,600	'	'
Due to related-parties	0	0	'	'
Deferred revenue, current	54,613	35,977	'	'
Total current liabilities	238,174	263,234	'	'
Long-term debt, non-current	2,811,323	2,814,505	'	'
Related party debt, long-term	0	0	'	'
Capital lease obligations, non-current	15,685	6,567	'	'
Deferred revenue, non-current	334,386	326,180	'	'
Stock-based compensation liability	201,063	158,520	'	'
Deferred income taxes, net	7,374	5,560	'	'
Other long-term liabilities	19,775	19,892	'	'
Total liabilities	3,627,780	3,594,458	'	'
Member's interest	707,713	703,963	'	'
Accumulated other comprehensive income/(loss)	4,704	-4,755	'	'
(Accumulated deficit)/retained earnings	-193,698	-165,775	'	'
Total member's equity	518,719	533,433	'	'
Total liabilities and member's equity	4,146,499	4,127,891	'	'
Zayo Group, LLC [Member]	'	'	'	'
Cash and cash equivalents	88,146	83,608	202,266	149,574
Trade receivables, net	40,920	52,377	'	'
Due from related parties	533	2,113	'	'
Prepaid expenses	13,519	14,768	'	'
Deferred income taxes	30,600	30,600	'	'
Restricted cash	'	0	'	'
Other assets, current	1,931	2,843	'	'
Total current assets	175,649	186,309	'	'
Property and equipment, net	2,291,534	2,274,764	'	'
Intangible assets, net	575,681	585,590	'	'
Goodwill	620,456	620,812	'	'
Debt issuance costs, net	95,901	99,098	'	'
Deferred income taxes, net	53,732	60,036	'	'
Other assets, non-current	24,305	25,332	'	'
Related party receivable, long-term	10,500	10,427	'	'
Investment in subsidiary	231,567	216,224	'	'
Total assets	4,079,325	4,078,592	'	'
Current portion of long-term debt	16,200	16,200	'	'
Accounts payable	17,550	30,319	'	'
Accrued liabilities	98,246	103,780	'	'
Accrued interest	26,387	55,048	'	'
Capital lease obligations, current	1,881	1,493	'	'
Due to related-parties	-2,198	25	'	'
Deferred revenue, current	51,671	33,170	'	'
Total current liabilities	209,737	240,035	'	'
Long-term debt, non-current	2,811,323	2,814,505	'	'
Related party debt, long-term	0	0	'	'
Capital lease obligations, non-current	5,865	6,487	'	'
Deferred revenue, non-current	327,212	318,188	'	'
Stock-based compensation liability	195,279	154,435	'	'
Deferred income taxes, net	0	0	'	'
Other long-term liabilities	11,190	11,511	'	'
Total liabilities	3,560,606	3,545,161	'	'
Member's interest	755,407	736,439	'	'
Accumulated other comprehensive income/(loss)	0	0	'	'
(Accumulated deficit)/retained earnings	-236,688	-203,008	'	'
Total member's equity	518,719	533,431	'	'
Total liabilities and member's equity	4,079,325	4,078,592	'	'
Zayo Colocation Inc [Member]	'	'	'	'
Cash and cash equivalents	1,013	1,009	2,432	1,119
Trade receivables, net	5,122	4,284	'	'
Due from related parties	0	0	'	'
Prepaid expenses	2,239	1,634	'	'
Deferred income taxes	0	0	'	'
Restricted cash	'	0	'	'
Other assets, current	6	6	'	'
Total current assets	8,380	6,933	'	'
Property and equipment, net	61,893	48,673	'	'
Intangible assets, net	18,036	18,695	'	'
Goodwill	15,058	15,055	'	'
Debt issuance costs, net	0	0	'	'
Deferred income taxes, net	0	0	'	'
Other assets, non-current	3,750	3,130	'	'
Related party receivable, long-term	0	0	'	'
Investment in subsidiary	0	0	'	'
Total assets	107,117	92,486	'	'
Current portion of long-term debt	0	0	'	'
Accounts payable	923	1,536	'	'
Accrued liabilities	5,968	5,376	'	'
Accrued interest	0	0	'	'
Capital lease obligations, current	5,731	5,107	'	'
Due to related-parties	0	0	'	'
Deferred revenue, current	882	701	'	'
Total current liabilities	13,504	12,720	'	'
Long-term debt, non-current	0	0	'	'
Related party debt, long-term	0	0	'	'
Capital lease obligations, non-current	9,820	80	'	'
Deferred revenue, non-current	3,920	3,850	'	'
Stock-based compensation liability	3,703	2,794	'	'
Deferred income taxes, net	0	0	'	'
Other long-term liabilities	8,517	8,311	'	'
Total liabilities	39,464	27,755	'	'
Member's interest	33,874	33,748	'	'
Accumulated other comprehensive income/(loss)	0	0	'	'
(Accumulated deficit)/retained earnings	33,779	30,983	'	'
Total member's equity	67,653	64,731	'	'
Total liabilities and member's equity	107,117	92,486	'	'
Non-Guarantor Subsidiaries [Member]	'	'	'	'
Cash and cash equivalents	3,274	3,531	9,032	0
Trade receivables, net	16,494	11,150	'	'
Due from related parties	0	-384	'	'
Prepaid expenses	2,915	2,786	'	'
Deferred income taxes	0	0	'	'
Restricted cash	'	0	'	'
Other assets, current	52	2	'	'
Total current assets	22,735	17,085	'	'
Property and equipment, net	95,337	87,783	'	'
Intangible assets, net	33,477	31,973	'	'
Goodwill	49,770	46,908	'	'
Debt issuance costs, net	0	0	'	'
Deferred income taxes, net	0	0	'	'
Other assets, non-current	805	822	'	'
Related party receivable, long-term	0	0	'	'
Investment in subsidiary	0	0	'	'
Total assets	202,124	184,571	'	'
Current portion of long-term debt	0	0	'	'
Accounts payable	2,449	1,622	'	'
Accrued liabilities	8,226	6,776	'	'
Accrued interest	0	0	'	'
Capital lease obligations, current	0	0	'	'
Due to related-parties	2,198	1,082	'	'
Deferred revenue, current	2,060	2,106	'	'
Total current liabilities	14,933	11,586	'	'
Long-term debt, non-current	0	0	'	'
Related party debt, long-term	10,500	10,427	'	'
Capital lease obligations, non-current	0	0	'	'
Deferred revenue, non-current	3,254	4,142	'	'
Stock-based compensation liability	2,081	1,291	'	'
Deferred income taxes, net	7,374	5,560	'	'
Other long-term liabilities	68	70	'	'
Total liabilities	38,210	33,076	'	'
Member's interest	149,999	150,000	'	'
Accumulated other comprehensive income/(loss)	4,704	-4,755	'	'
(Accumulated deficit)/retained earnings	9,211	6,250	'	'
Total member's equity	163,914	151,495	'	'
Total liabilities and member's equity	202,124	184,571	'	'
Eliminations [Member]	'	'	'	'
Cash and cash equivalents	0	0	'	'
Trade receivables, net	0	0	'	'
Due from related parties	0	-1,107	'	'
Prepaid expenses	0	0	'	'
Deferred income taxes	0	0	'	'
Restricted cash	'	0	'	'
Other assets, current	0	0	'	'
Total current assets	0	-1,107	'	'
Property and equipment, net	0	0	'	'
Intangible assets, net	0	0	'	'
Goodwill	0	0	'	'
Debt issuance costs, net	0	0	'	'
Deferred income taxes, net	0	0	'	'
Other assets, non-current	0	0	'	'
Related party receivable, long-term	-10,500	-10,427	'	'
Investment in subsidiary	-231,567	-216,224	'	'
Total assets	-242,067	-227,758	'	'
Current portion of long-term debt	0	0	'	'
Accounts payable	0	0	'	'
Accrued liabilities	0	0	'	'
Accrued interest	0	0	'	'
Capital lease obligations, current	0	0	'	'
Due to related-parties	0	-1,107	'	'
Deferred revenue, current	0	0	'	'
Total current liabilities	0	-1,107	'	'
Long-term debt, non-current	0	0	'	'
Related party debt, long-term	-10,500	-10,427	'	'
Capital lease obligations, non-current	0	0	'	'
Deferred revenue, non-current	0	0	'	'
Stock-based compensation liability	0	0	'	'
Deferred income taxes, net	0	0	'	'
Other long-term liabilities	0	0	'	'
Total liabilities	-10,500	-11,534	'	'
Member's interest	-231,567	-216,224	'	'
Accumulated other comprehensive income/(loss)	0	0	'	'
(Accumulated deficit)/retained earnings	0	0	'	'
Total member's equity	-231,567	-216,224	'	'
Total liabilities and member's equity	($242,067)	($227,758)	'	'

Condensed_Consolidating_Financ4

Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Statements Of Operations) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012
Revenue	$264,345	'	'	'	$231,502
Operating costs, excluding depreciation and amortization	34,882	'	'	'	32,717
Selling, general and administrative expenses, excluding stock-based compensation	74,732	'	'	'	85,792
Stock-based compensation	42,684	'	'	'	10,481
Selling, general and administrative expenses	117,416	'	'	'	96,273
Depreciation and amortization	80,575	'	'	'	79,549
Total operating costs and expenses	232,873	'	'	'	208,539
Operating income	31,472	'	'	'	22,963
Interest expense	-51,497	'	'	'	-62,555
Loss on extinguishment of debt	0	'	'	'	-64,975
Other income, net	663	'	'	'	585
Equity in net earnings of subsidiaries	0	'	'	'	0
Total other expense, net	-50,834	'	'	'	-126,945
Loss from continuing operations before provision for income taxes	-19,362	'	'	'	-103,982
(Benefit)/provision for income taxes	8,534	9,460	6,519	-3,438	-36,588
Loss from continuing operations	-27,896	'	'	'	-67,394
Earnings from discontinued operations, net of income taxes	0	'	'	'	1,808
Net (loss)/earnings	-27,896	-24,386	-18,543	-34,241	-65,586
Zayo Group, LLC [Member]	'	'	'	'	'
Revenue	230,821	'	'	'	201,919
Operating costs, excluding depreciation and amortization	24,880	'	'	'	23,115
Selling, general and administrative expenses, excluding stock-based compensation	65,513	'	'	'	73,434
Stock-based compensation	41,078	'	'	'	10,125
Selling, general and administrative expenses	106,591	'	'	'	83,559
Depreciation and amortization	74,972	'	'	'	74,207
Total operating costs and expenses	206,443	'	'	'	180,881
Operating income	24,378	'	'	'	21,038
Interest expense	-51,013	'	'	'	-62,443
Loss on extinguishment of debt	'	'	'	'	-64,975
Other income, net	39	'	'	'	35
Equity in net earnings of subsidiaries	5,787	'	'	'	1,362
Total other expense, net	-45,187	'	'	'	-126,021
Loss from continuing operations before provision for income taxes	-20,809	'	'	'	-104,983
(Benefit)/provision for income taxes	7,087	'	'	'	-37,589
Loss from continuing operations	-27,896	'	'	'	-67,394
Earnings from discontinued operations, net of income taxes	0	'	'	'	1,808
Net (loss)/earnings	-27,896	'	'	'	-65,586
Zayo Colocation Inc [Member]	'	'	'	'	'
Revenue	18,709	'	'	'	15,072
Operating costs, excluding depreciation and amortization	8,536	'	'	'	7,696
Selling, general and administrative expenses, excluding stock-based compensation	3,732	'	'	'	4,451
Stock-based compensation	909	'	'	'	154
Selling, general and administrative expenses	4,641	'	'	'	4,605
Depreciation and amortization	2,325	'	'	'	2,049
Total operating costs and expenses	15,502	'	'	'	14,350
Operating income	3,207	'	'	'	722
Interest expense	-412	'	'	'	3
Loss on extinguishment of debt	'	'	'	'	0
Other income, net	1	'	'	'	0
Equity in net earnings of subsidiaries	0	'	'	'	0
Total other expense, net	-411	'	'	'	3
Loss from continuing operations before provision for income taxes	2,796	'	'	'	725
(Benefit)/provision for income taxes	0	'	'	'	0
Loss from continuing operations	2,796	'	'	'	725
Earnings from discontinued operations, net of income taxes	0	'	'	'	0
Net (loss)/earnings	2,796	'	'	'	725
Non-Guarantor Subsidiaries [Member]	'	'	'	'	'
Revenue	14,815	'	'	'	14,511
Operating costs, excluding depreciation and amortization	1,466	'	'	'	1,906
Selling, general and administrative expenses, excluding stock-based compensation	5,487	'	'	'	7,907
Stock-based compensation	697	'	'	'	202
Selling, general and administrative expenses	6,184	'	'	'	8,109
Depreciation and amortization	3,278	'	'	'	3,293
Total operating costs and expenses	10,928	'	'	'	13,308
Operating income	3,887	'	'	'	1,203
Interest expense	-72	'	'	'	-115
Loss on extinguishment of debt	'	'	'	'	0
Other income, net	623	'	'	'	550
Equity in net earnings of subsidiaries	0	'	'	'	0
Total other expense, net	551	'	'	'	435
Loss from continuing operations before provision for income taxes	4,438	'	'	'	1,638
(Benefit)/provision for income taxes	1,447	'	'	'	1,001
Loss from continuing operations	2,991	'	'	'	637
Earnings from discontinued operations, net of income taxes	0	'	'	'	0
Net (loss)/earnings	2,991	'	'	'	637
Eliminations [Member]	'	'	'	'	'
Revenue	0	'	'	'	0
Operating costs, excluding depreciation and amortization	0	'	'	'	0
Selling, general and administrative expenses, excluding stock-based compensation	0	'	'	'	0
Stock-based compensation	0	'	'	'	0
Selling, general and administrative expenses	0	'	'	'	0
Depreciation and amortization	0	'	'	'	0
Total operating costs and expenses	0	'	'	'	0
Operating income	0	'	'	'	0
Interest expense	0	'	'	'	0
Loss on extinguishment of debt	'	'	'	'	0
Other income, net	0	'	'	'	0
Equity in net earnings of subsidiaries	-5,787	'	'	'	-1,362
Total other expense, net	-5,787	'	'	'	-1,362
Loss from continuing operations before provision for income taxes	-5,787	'	'	'	-1,362
(Benefit)/provision for income taxes	0	'	'	'	0
Loss from continuing operations	-5,787	'	'	'	-1,362
Earnings from discontinued operations, net of income taxes	0	'	'	'	0
Net (loss)/earnings	($5,787)	'	'	'	($1,362)

Condensed_Consolidating_Financ5

Condensed Consolidating Financial Information (Schedule Of Condensed Consolidating Statements Of Cash Flows) (Details) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013	Sep. 30, 2012	Jun. 30, 2013
Net cash provided by operating activities of continuing operations	$93,877	$79,070	'
Purchases of property and equipment	-86,672	-70,163	'
Purchases of property and equipment, net of stimulus grants	'	-66,656	'
Acquisitions, net of cash acquired	-294	-2,328,165	-2,485,809
Net cash used in investing activities of continuing operations	-86,966	-2,394,821	'
Equity contributions	1,881	337,203	'
Principal repayments on capital lease obligations	-397	-378	'
Proceeds from issuance of long-term debt	0	2,840,000	'
Principal repayments on long-term debt	-4,050	-697,475	'
Payment of early redemption fees on debt extinguished	0	-39,797	'
Change in restricted cash, net	0	22,415	'
Cash contributed to ZPS	0	-2,424	'
Deferred financing costs	-183	-82,508	'
Net cash (used in)/provided by financing activities of continuing operations	-2,749	2,377,036	'
Cash flows from discontinued operations	0	1,544	'
Effect of changes in foreign exchange rates on cash	123	208	'
Net decrease in cash and cash equivalents	4,285	63,037	'
Cash and cash equivalents, beginning of period	88,148	150,693	150,693
Cash and cash equivalents, end of period	92,433	213,730	88,148
Zayo Group, LLC [Member]	'	'	'
Payments of Dividends	'	636	'
Net cash provided by operating activities of continuing operations	83,383	71,435	'
Purchases of property and equipment	-80,520	'	'
Purchases of property and equipment, net of stimulus grants	'	-61,901	'
Acquisitions, net of cash acquired	0	-2,336,057	'
Net cash used in investing activities of continuing operations	-80,520	-2,397,958	'
Equity contributions	1,881	337,203	'
Principal repayments on capital lease obligations	-251	-378	'
Proceeds from issuance of long-term debt	'	2,840,000	'
Principal repayments on long-term debt	-4,050	-697,475	'
Payment of early redemption fees on debt extinguished	'	-39,797	'
Change in restricted cash, net	'	22,415	'
Cash contributed to ZPS	'	-2,424	'
Deferred financing costs	-183	-82,508	'
Net cash (used in)/provided by financing activities of continuing operations	1,675	2,377,672	'
Cash flows from discontinued operations	'	1,544	'
Effect of changes in foreign exchange rates on cash	0	0	'
Net decrease in cash and cash equivalents	4,538	52,692	'
Cash and cash equivalents, beginning of period	83,608	149,574	149,574
Cash and cash equivalents, end of period	88,146	202,266	'
Zayo Colocation Inc [Member]	'	'	'
Payments of Dividends	'	636	'
Net cash provided by operating activities of continuing operations	7,521	5,202	'
Purchases of property and equipment	-2,799	'	'
Purchases of property and equipment, net of stimulus grants	'	-3,253	'
Acquisitions, net of cash acquired	-294	0	'
Net cash used in investing activities of continuing operations	-3,093	-3,253	'
Equity contributions	0	0	'
Principal repayments on capital lease obligations	-146	0	'
Proceeds from issuance of long-term debt	'	0	'
Principal repayments on long-term debt	0	0	'
Payment of early redemption fees on debt extinguished	'	0	'
Change in restricted cash, net	'	0	'
Cash contributed to ZPS	'	0	'
Deferred financing costs	0	0	'
Net cash (used in)/provided by financing activities of continuing operations	-4,424	-636	'
Cash flows from discontinued operations	'	0	'
Effect of changes in foreign exchange rates on cash	0	0	'
Net decrease in cash and cash equivalents	4	1,313	'
Cash and cash equivalents, beginning of period	1,009	1,119	1,119
Cash and cash equivalents, end of period	1,013	2,432	'
Non-Guarantor Subsidiaries [Member]	'	'	'
Net cash provided by operating activities of continuing operations	2,973	2,433	'
Purchases of property and equipment	-3,353	'	'
Purchases of property and equipment, net of stimulus grants	'	-1,502	'
Acquisitions, net of cash acquired	0	7,892	'
Net cash used in investing activities of continuing operations	-3,353	6,390	'
Equity contributions	0	0	'
Principal repayments on capital lease obligations	0	0	'
Proceeds from issuance of long-term debt	'	0	'
Principal repayments on long-term debt	0	0	'
Payment of early redemption fees on debt extinguished	'	0	'
Change in restricted cash, net	'	0	'
Cash contributed to ZPS	'	0	'
Deferred financing costs	0	0	'
Net cash (used in)/provided by financing activities of continuing operations	0	0	'
Cash flows from discontinued operations	'	0	'
Effect of changes in foreign exchange rates on cash	123	208	'
Net decrease in cash and cash equivalents	-257	9,032	'
Cash and cash equivalents, beginning of period	3,531	0	0
Cash and cash equivalents, end of period	$3,274	$9,032	'

Subsequent_Events_Narrative_De

Subsequent Events (Narrative) (Details) (Subsequent Event [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Sep. 30, 2013
Subsequent Event [Member]	'
Subsequent Event [Line Items]	'
Non-liquidating cash distribution authorized	$10,000
Percentage of distribution received due to early distribution	90.00%
Discount on early distributions	0.00%
Non-liquidating distributions	9,865
Amount forfeited due to early distribution	$1,096