Consolidated Statements of Shareholders' Equity - USD ($)	Common Stock [Member] Common Class A [Member]	Common Stock [Member] Common Class B [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]	Common Class A [Member]	Common Class B [Member]	Total
Balances at Dec. 31, 2012	$ 25,000	$ 4,000	$ 39,493,000	$ 44,700,000	$ 1,124,000	$ (28,604,000)			$ 56,742,000
Purchase of treasury stock						(206,000)			(206,000)
Issuance of shares for the exercise of stock options			990,000						990,000
Tax benefit from the exercise of options and restricted stock			755,000						755,000
Non-cash stock compensation expense			955,000						955,000
Fractional share cashed out			(1,000)						(1,000)
Dividends declared				(2,142,000)					(2,142,000)
Other comprehensive loss, foreign currency translation adjustment					(822,000)				(822,000)
Net income				15,484,000			$ 7,741,000	$ 7,743,000	15,484,000
Balances at Dec. 31, 2013	25,000	4,000	42,192,000	58,042,000	302,000	(28,810,000)			71,755,000
Other comprehensive loss, foreign currency translation adjustment									(822,000)
Purchase of treasury stock						(1,248,000)			(1,248,000)
Issuance of shares for the exercise of stock options			1,308,000						1,308,000
Tax benefit from the exercise of options and restricted stock			622,000						622,000
Non-cash stock compensation expense			742,000						742,000
Dividends declared				(2,512,000)					(2,512,000)
Other comprehensive loss, foreign currency translation adjustment					(1,075,000)				(1,075,000)
Net income				18,156,000			9,062,000	9,094,000	18,156,000
Balances at Dec. 31, 2014	25,000	4,000	44,864,000	73,686,000	(773,000)	(30,058,000)			87,748,000
Other comprehensive loss, foreign currency translation adjustment									(1,075,000)
Purchase of treasury stock						(2,171,000)			(2,171,000)
Issuance of shares for the exercise of stock options			406,000						406,000
Tax benefit from the exercise of options and restricted stock			240,000						240,000
Non-cash stock compensation expense			1,383,000						1,383,000
Dividends declared				(25,983,000)					(25,983,000)
Net income				17,610,000			$ 8,759,000	$ 8,851,000	17,610,000
Balances at Dec. 31, 2015	26,000	$ 4,000	44,103,000	$ 65,313,000	(2,995,000)	$ (32,229,000)			74,222,000
Issuance of restricted common shares, net of forfeitures (73,168 class A and 12,194 class B)	$ 1		(1)
Acquisition of non-controlling interest			$ (2,789,000)						(2,789,000)
Other comprehensive loss, foreign currency translation adjustment					$ (2,222,000)				$ (2,222,000)