Nature of Business and Significant Accounting Policies - Other (Details) $ / shares in Units, $ in Thousands			3 Months Ended												12 Months Ended
	Nov. 30, 2016 item	Apr. 01, 2014 USD ($) item	Dec. 31, 2016 USD ($) $ / shares	Sep. 30, 2016 USD ($) $ / shares	Jun. 30, 2016 USD ($) $ / shares	Mar. 31, 2016 USD ($) $ / shares	Dec. 31, 2015 USD ($) $ / shares	Sep. 30, 2015 USD ($) $ / shares	Jun. 30, 2015 USD ($) $ / shares	Mar. 31, 2015 USD ($) $ / shares	Dec. 31, 2014 USD ($) $ / shares	Sep. 30, 2014 USD ($) $ / shares	Jun. 30, 2014 USD ($) $ / shares	Mar. 31, 2014 USD ($) $ / shares	Dec. 31, 2016 USD ($) segment $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares
Nature of business
Number of operating segments | segment															1
Assets acquired in cash																	$ 101,891
Reclassification
Assets			$ 530,441				$ 548,896								$ 530,441	$ 548,896
Liabilities			261,101				270,255								261,101	270,255
Numerator for earnings per common share calculation:
Net income			$ 5,922	$ 4,349	$ 5,029	$ 2,700	$ 4,934	$ 2,910	$ 3,431	$ 2,462	$ 4,330	$ 663	$ 5,318	$ 248	$ 18,000	$ 13,739	$ 10,557
Denominator for earnings per common share calculation:
Weighted-average common shares, basic | shares															41,666,000	42,840,000	42,321,000
Effect of dilutive securities:
Stock options, restricted stock and warrants | shares															608,000	962,000	301
Weighted-average common shares, diluted | shares															42,274,000	43,802,000	42,622,000
EPS
Basic (in dollars per share) | $ / shares			$ 0.15	$ 0.11	$ 0.12	$ 0.06	$ 0.11	$ 0.07	$ 0.08	$ 0.06	$ 0.10	$ 0.02	$ 0.13	$ 0.01	$ 0.43	$ 0.32	$ 0.25
Diluted (in dollars per share) | $ / shares			$ 0.15	$ 0.11	$ 0.12	$ 0.06	$ 0.11	$ 0.07	$ 0.08	$ 0.06	$ 0.10	$ 0.02	$ 0.13	$ 0.01	$ 0.43	$ 0.31	$ 0.25
Shares excluded from the computation of diluted income per common share | shares															1,900,000	1,000,000	1,100,000
ASU 2015-03 | Adjustment
Reclassification
Assets			$ (2,300)												$ (2,300)
Liabilities			$ (2,300)												$ (2,300)
Colombian content producers, Radio television and NTC nacional | Television broadcast license
Nature of business
License life (in years)	10 years
Number of national broadcast television licenses | item	3
Cable Networks Acquisition
Nature of business
Number of Spanish-language cable television networks whose assets are acquired | item		3
Assets acquired in cash		$ 101,900