Quarterly report pursuant to Section 13 or 15(d)

Consolidated Statements of Cash Flows Supplemental Disclosures (Changes in operating assets and liabilities) (Details)

v2.4.1.9
Consolidated Statements of Cash Flows Supplemental Disclosures (Changes in operating assets and liabilities) (Details) (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Supplemental Cash Flow Elements [Abstract]    
Decrease in accounts receivable, net $ 7,859us-gaap_IncreaseDecreaseInAccountsReceivable $ 8,295us-gaap_IncreaseDecreaseInAccountsReceivable
Increase in prepaid expenses (308)us-gaap_IncreaseDecreaseInPrepaidExpense (3,581)us-gaap_IncreaseDecreaseInPrepaidExpense
Decrease in inventories 2,495us-gaap_IncreaseDecreaseInInventories 3,653us-gaap_IncreaseDecreaseInInventories
Decrease in other current assets 7us-gaap_IncreaseDecreaseInOtherCurrentAssets 26us-gaap_IncreaseDecreaseInOtherCurrentAssets
Increase in other assets (1,250)us-gaap_IncreaseDecreaseInOtherNoncurrentAssets (142)us-gaap_IncreaseDecreaseInOtherNoncurrentAssets
Decrease in accounts payable (2,470)us-gaap_IncreaseDecreaseInAccountsPayable (8,594)us-gaap_IncreaseDecreaseInAccountsPayable
Increase (decrease) in deferred revenues (2,256)gncma_IncreaseDecreaseInDeferredRevenueCurrent 1,462gncma_IncreaseDecreaseInDeferredRevenueCurrent
Decrease in accrued payroll and payroll related obligations (6,083)us-gaap_IncreaseDecreaseInAccruedSalaries (8,476)us-gaap_IncreaseDecreaseInAccruedSalaries
Increase in accrued liabilities 3,891us-gaap_IncreaseDecreaseInOtherAccruedLiabilities 1,015us-gaap_IncreaseDecreaseInOtherAccruedLiabilities
Increase in accrued interest 17,611us-gaap_IncreaseDecreaseInInterestPayableNet 14,363us-gaap_IncreaseDecreaseInInterestPayableNet
Decrease in subscriber deposits (153)us-gaap_IncreaseDecreaseInCustomerDeposits (140)us-gaap_IncreaseDecreaseInCustomerDeposits
Decrease in long-term deferred revenue (251)gncma_IncreaseDecreaseInDeferredRevenueNoncurrent (1,375)gncma_IncreaseDecreaseInDeferredRevenueNoncurrent
Increase (decrease) in components of other long-term liabilities (255)us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities 645us-gaap_IncreaseDecreaseInOtherNoncurrentLiabilities
Total change in operating assets and liabilities $ 18,837us-gaap_IncreaseDecreaseInOperatingCapital $ 7,151us-gaap_IncreaseDecreaseInOperatingCapital