Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies - Narrative (Details)

v2.4.1.9
Summary of Significant Accounting Policies - Narrative (Details) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Accounting Policies [Abstract]      
Trade receivables, allowance for doubtful accounts (in dollars) $ 2,120us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent $ 1,937us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent  
Finite-Lived Intangible Assets [Line Items]      
Amortization of subscriber accounts, dealer network and other intangible assets 253,403us-gaap_AmortizationOfIntangibleAssets 208,760us-gaap_AmortizationOfIntangibleAssets 163,468us-gaap_AmortizationOfIntangibleAssets
Subscriber Accounts      
Finite-Lived Intangible Assets [Line Items]      
Intangible Assets, Weighted Average Useful Life 15 years    
Finite Lived Intangible Asset Amortization Rate 220.00%mtii_AcquiredFiniteLivedIntangibleAssetAmortizationRate
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= mtii_SubscriberAccountsMember
   
Amortization of subscriber accounts, dealer network and other intangible assets 233,327us-gaap_AmortizationOfIntangibleAssets
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= mtii_SubscriberAccountsMember
195,010us-gaap_AmortizationOfIntangibleAssets
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= mtii_SubscriberAccountsMember
153,388us-gaap_AmortizationOfIntangibleAssets
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= mtii_SubscriberAccountsMember
Dealer Networks and Other Intangible Assets      
Finite-Lived Intangible Assets [Line Items]      
Amortization of subscriber accounts, dealer network and other intangible assets $ 19,780us-gaap_AmortizationOfIntangibleAssets
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= mtii_DealerNetworksAndOtherIntangibleAssetsMember
$ 13,717us-gaap_AmortizationOfIntangibleAssets
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= mtii_DealerNetworksAndOtherIntangibleAssetsMember
$ 10,080us-gaap_AmortizationOfIntangibleAssets
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= mtii_DealerNetworksAndOtherIntangibleAssetsMember
Security Networks Acquisition | Subscriber Accounts      
Finite-Lived Intangible Assets [Line Items]      
Intangible Assets, Weighted Average Useful Life 14 years    
Finite Lived Intangible Asset Amortization Rate 235.00%mtii_AcquiredFiniteLivedIntangibleAssetAmortizationRate
/ us-gaap_BusinessAcquisitionAxis
= mtii_SecurityNetworksLLCAndCertainAffiliatedEntitiesMember
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= mtii_SubscriberAccountsMember