Earnings (Loss) per Common Share (Diluted Net Income (Loss) Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Common Stock - Class A [Member]
Numerator:
Undistributed net income (loss) allocable to common stockholders for basic computation	$ (8,086)	$ 2,967	$ (58,207)	$ 3,934
Reallocation of undistributed earnings as a result of conversion of Class B to Class A shares	(796)	281	(5,804)	370
Reallocation of undistributed earnings as a result of conversion of dilutive securities	0	189	0	304
Effect of derivative instrument that may be settled in cash or shares	0	(3,834)	0	(6,501)
Effect of share based compensation that may be settled in cash or shares	0	(39)	0	(62)
Undistributed net loss adjusted for allocation of undistributed earnings (loss) and effect of contracts that may be settled in cash or shares	$ (8,882)	$ (436)	$ (64,011)	$ (1,955)
Denominator:
Number of shares used in basic computation	31,276	33,308	31,248	33,502
Conversion of Class B to Class A common shares outstanding	3,078	3,155	3,116	3,155
Effect of derivative instrument that may be settled in cash or shares	0	611	0	744
Effect of share based compensation that may be settled in cash or shares	0	26	0	26
Number of shares used in per share computation	34,354	37,100	34,364	37,427
Diluted net loss attributable to GCI common stockholders per common share (USD per share)	$ (0.26)	$ (0.01)	$ (1.86)	$ (0.05)
Common Stock - Class B [Member]
Numerator:
Undistributed net income (loss) allocable to common stockholders for basic computation	$ (796)	$ 281	$ (5,804)	$ 370
Reallocation of undistributed earnings as a result of conversion of Class B to Class A shares	0	0	0	0
Reallocation of undistributed earnings as a result of conversion of dilutive securities	0	(319)	0	(536)
Effect of derivative instrument that may be settled in cash or shares	0	0	0	0
Effect of share based compensation that may be settled in cash or shares	0	0	0	0
Undistributed net loss adjusted for allocation of undistributed earnings (loss) and effect of contracts that may be settled in cash or shares	$ (796)	$ (38)	$ (5,804)	$ (166)
Denominator:
Number of shares used in basic computation	3,078	3,155	3,116	3,155
Conversion of Class B to Class A common shares outstanding	0	0	0	0
Effect of derivative instrument that may be settled in cash or shares	0	0	0	0
Effect of share based compensation that may be settled in cash or shares	0	0	0	0
Number of shares used in per share computation	3,078	3,155	3,116	3,155
Diluted net loss attributable to GCI common stockholders per common share (USD per share)	$ (0.26)	$ (0.01)	$ (1.86)	$ (0.05)