Consolidated Statements of Stockholders' Equity (USD $) In Thousands, except Share data, unless otherwise specified	Class A Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2009	$ 220	$ 191,701	$ 85,953	$ 7,804	$ (60,844)	$ 224,834
Balance (in shares) at Dec. 31, 2009	25,108,894
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	32,420	0	0	32,420
Foreign currency translation adjustment	0	0	0	3,443	0	3,443
Sale of Class A common stock	4	5,063	0	0	0	5,067
Sale of Class A common stock (in shares)	624,033
Tax benefit from stock options exercised	0	1,109	0	0	0	1,109
Stock issued under employee stock purchase plan	0	446	0	0	0	446
Stock issued under employee stock purchase plan (in shares)	26,423
Stock based compensation expense	0	1,886	0	0	0	1,886
Issuance of Class A common stock under dividend reinvestment program	0	0	(36)	0	36	0
Issuance of Class A common stock under dividend reinvestment program (in shares)	1,984
Cash dividends	0	0	(5,079)	0	0	(5,079)
Balance at Dec. 31, 2010	224	200,205	113,258	11,247	(60,808)	264,126
Balance (in shares) at Dec. 31, 2010	25,761,334
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	20,611	0	0	20,611
Foreign currency translation adjustment	0	0	0	(2,167)	0	(2,167)
Sale of Class A common stock	1	783	0	0	0	784
Sale of Class A common stock (in shares)	226,917
Tax benefit from stock options exercised	0	293	0	0	0	293
Stock issued under employee stock purchase plan	0	432	0	0	0	432
Stock issued under employee stock purchase plan (in shares)	33,348
Stock based compensation expense	0	2,098	0	0	0	2,098
Purchase of Class A treasury stock	0	0	0	0	(4,053)	(4,053)
Purchase of Class A treasury stock (in shares)	(322,241)
Issuance of Class A common stock under dividend reinvestment program	0	0	(51)	0	51	0
Issuance of Class A common stock under dividend reinvestment program (in shares)	3,767
Cash dividends	0	0	(8,199)	0	0	(8,199)
Balance at Dec. 31, 2011	225	203,811	125,619	9,080	(64,810)	273,925
Balance (in shares) at Dec. 31, 2011	25,703,125					25,703,125
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	(23,416)	0	0	(23,416)
Foreign currency translation adjustment	0	0	0	2,779	0	2,779
Sale of Class A common stock	2	1,969	0	0	0	1,971
Sale of Class A common stock (in shares)	373,091
Tax benefit from stock options exercised	0	244	0	0	0	244
Stock issued under employee stock purchase plan	0	403	0	0	0	403
Stock issued under employee stock purchase plan (in shares)	33,058
Stock based compensation expense	0	3,129	0	0	0	3,129
Issuance of Class A common stock under dividend reinvestment program	0	0	(54)	0	54	0
Issuance of Class A common stock under dividend reinvestment program (in shares)	4,270
Cash dividends	0	0	(8,252)	0	0	(8,252)
Balance at Dec. 31, 2012	$ 227	$ 209,556	$ 93,897	$ 11,859	$ (64,756)	$ 250,783
Balance (in shares) at Dec. 31, 2012	26,113,544					26,113,544