Consolidated Statement of Stockholders' Equity - 6 months ended Jun. 30, 2017 - USD ($)	Total	Additional Paid-In Capital [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Class A Common Stock [Member]	Class B Common Stock [Member]
Balance at Dec. 31, 2016	$ 438,615,320	$ 236,851,709	$ (2,254,271)	$ 244,942,913	$ (41,226,357)	$ 244,834	$ 56,492
Balance, shares at Dec. 31, 2016						24,483,377	5,649,240
Issuance of common stock	1,354,310	1,353,489				$ 821
Issuance of common stock, shares						82,068
Share-based compensation	3,402,316	3,400,748				$ 1,568
Share-based compensation, shares						156,831
Net income	2,786,170			2,786,170
Cash dividends declared	(3,728,839)			(3,728,839)
Grant of stock options		303,896		(303,896)
Other comprehensive income	702,789		702,789
Balance at Jun. 30, 2017	$ 443,132,066	$ 241,909,842	$ (1,551,482)	$ 243,696,348	$ (41,226,357)	$ 247,223	$ 56,492
Balance, shares at Jun. 30, 2017						24,722,276	5,649,240