Commitments and Contingencies (Details) $ in Thousands				1 Months Ended	3 Months Ended			9 Months Ended		49 Months Ended
	Nov. 08, 2017 USD ($) radio_station television_station	Aug. 16, 2017	Dec. 08, 2008 subsidiary	Feb. 29, 2012 USD ($)	Mar. 31, 2018 USD ($)	Sep. 30, 2017 USD ($) claim	Sep. 30, 2016 USD ($)	Sep. 30, 2017 USD ($) claim case	Sep. 30, 2016 USD ($)	Dec. 31, 2012 claim	Apr. 13, 2017 station	Dec. 31, 2016 USD ($)	Aug. 12, 2016 case
Loss Contingencies [Line Items]
Number of direct and indirect wholly-owned subsidiaries included in bankruptcy filing | subsidiary			110
Number of proofs of claim settled or satisfied pursuant to the terms of the plan | case													106
Number of complaints filed | claim										7,400
Restricted cash and cash equivalents						$ 17,566		$ 17,566				$ 17,566
Number of proofs of claim subject to further evaluation and adjustments | claim						403		403
Reorganization Items						$ (753)	$ (434)	$ (1,452)	$ (1,234)
Federal Communications Commission Regulation, Television Station Ownership Cap, Percent						39.00%		39.00%
The UHF Discount, Percent						50.00%		50.00%
FCC regulation, maximum reimbursement amount for required product modifications				$ 1,750,000
Repayments of long-term debt								$ 703,527	20,881
Proceeds from FCC spectrum auction								172,102	$ 0
Proceeds from Spectrum, Sharing Arrangement, Pretax								79,000
Payments for Spectrum, Sharing Arrangements, Pretax								$ 66,000
Number of Stations Subject to Spectrum Frequency Transition | station											22
Loss Contingency, Number of Filed Complaints | case								4
Third Party Involved in Claim, Participated in the Sale		4
Third Party Involved in Claim, Confidentiality Agreement		23
Amended Secured Credit Facility | Term Loan Facility
Loss Contingencies [Line Items]
Repayments of long-term debt						$ 102,000
Dreamcatcher Credit Facility Due 2018
Loss Contingencies [Line Items]
Repayments of long-term debt						12,600
Dreamcatcher Stations
Loss Contingencies [Line Items]
Proceeds Received From FCC Spectrum Auction						21,000
Repayments of long-term debt						$ 12,600
Subsequent Event
Loss Contingencies [Line Items]
FCC regulation, number of television stations authorized | television_station	39
FCC regulation, number of radio stations authorized | radio_station	1
Proceeds Received From FCC Spectrum Auction	$ 185,000
Proceeds Remaining to Receive From FCC Spectrum Auction	$ 5,000
Subsequent Event | FCC Licenses
Loss Contingencies [Line Items]
(Gain) Loss on Disposition of Intangible Assets					$ 133,000