Summary of Significant Accounting Policies (Details Textual)						1 Months Ended						3 Months Ended								12 Months Ended
	Nov. 21, 2016 USD ($) $ / shares	Jun. 01, 2016 USD ($) $ / shares	Mar. 02, 2016 USD ($) $ / shares	Jun. 10, 2015 USD ($) $ / shares	Dec. 03, 2014 USD ($) $ / shares	Aug. 30, 2016 USD ($) $ / shares	Nov. 17, 2015 USD ($) $ / shares	Sep. 02, 2015 USD ($) $ / shares	Mar. 25, 2015 USD ($) $ / shares	Sep. 23, 2014 USD ($) $ / shares	Jun. 30, 2014 USD ($) $ / shares	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($)	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($)	Dec. 31, 2016 USD ($) $ / shares shares	Dec. 31, 2015 USD ($) $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares
Summary Of Significant Accounting Policies [Line Items]
Number of stock options outstanding having antidilutive effect | shares																				0	0	45,000
Concentration Risk, Market Risk																				46.00%	44.00%	43.00%
Depreciation expense																				$ 6,621,000	$ 6,593,000	$ 6,648,000
Interest expense related to the amortization of debt issuance costs																				53,000	131,000	187,000
Write-off of debt issuance costs												$ 0	$ 0	$ 0	$ 0	$ 0	$ 557,000	$ 0	$ 0	0	557,000	$ 0
Net book value of deferred costs												$ 191,000				$ 244,000				$ 191,000	$ 244,000
Treasury Stock, Shares, Acquired | shares																				18,612	129,384	6,165
Treasury Stock Acquired, Average Cost Per Share | $ / shares																				$ 40.06	$ 36.53	$ 41.15
Advertising and promotion costs																				$ 2,975,000	$ 2,804,000	$ 3,056,000
Special cash dividend declared on Classes A and B Common Stock | $ / shares	$ 0.30	$ 0.25	$ 0.25	$ 0.20	$ 1.20	$ 0.30	$ 0.25	$ 0.20	$ 0.20	$ 0.20	$ 0.20									$ 1.30	$ 1.10	$ 1.80
Dividend paid	$ 2,900,000	$ 1,500,000	$ 1,500,000	$ 1,200,000	$ 8,200,000	$ 1,800,000	$ 2,900,000	$ 1,200,000	$ 1,200,000	$ 1,100,000	$ 1,100,000
Number Of Broadcast Licenses												108								108
Number Of Market Serving												26								26
Dividends Payable, Amount Per Share | $ / shares	$ 0.20				$ 0.20		$ 0.25
Class A Common Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Stock Repurchase Program, Remaining Authorized Repurchase Amount												$ 24,200,000								$ 24,200,000
Minimum [Member] | Class A Common Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Stock Repurchase Program, Authorized Amount												60,000,000								60,000,000
Maximum [Member] | Class A Common Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Stock Repurchase Program, Authorized Amount												$ 75,800,000								$ 75,800,000
Favorable Lease Agreements [Member] | Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Amortized over the lives of the leases term range																				5 years
Favorable Lease Agreements [Member] | Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Amortized over the lives of the leases term range																				26 years