Operations and Summary of Significant Accounting Policies (Details 2) (USD $) Share data in Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011 cent right series bank vote	Dec. 31, 2010	Dec. 31, 2009
Common Stock
Number of votes for each share of common stock held									1
Number of rights per common stock as a part of dividend distribution									1
Percentage acquisition of common stock triggering exercise terms of rights, minimum									15.00%
Ownership interest held by any stockholder at date of rights distribution to which additional exercise terms for the Rights distributed apply (as a percent)									25.00%
Subsequent increase in ownership interest held by any stockholder after rights distribution to which additional exercise terms for the Rights distributed apply (as a percent)									40.00%
Redemption price per right (in cents per right)									1
Preferred Stock
Number of series by which the Board may issue authorized and unissued preferred stock, minimum									1
Reconciliation of basic earnings per share ("EPS") to diluted EPS
Earnings from continuing operations, net of tax	$ 4,948,000	$ 19,380,000	$ 19,493,000	$ 7,078,000	$ (4,499,000)	$ 18,408,000	$ 21,059,000	$ 9,830,000	$ 50,900,000	$ 44,798,000	$ 14,121,000
Loss from discontinued operations, net of tax						(1,226,000)	(14,356,000)	(631,000)		(16,212,000)	(1,904,000)
Net income	4,948,000	19,380,000	19,493,000	7,078,000	(4,499,000)	17,182,000	6,703,000	9,199,000	50,900,000	28,586,000	12,217,000
Basic weighted average shares outstanding									48,974	49,498	49,135
Dilutive effect of potential common stock equivalents - stock options (in shares)									49	114	121
Diluted weighted average shares outstanding									49,023	49,612	49,256
Net earnings (loss) per share - basic:
Continuing operations (in dollars per share)	$ 0.10	$ 0.40	$ 0.39	$ 0.14	$ (0.09)	$ 0.37	$ 0.43	$ 0.20	$ 1.04	$ 0.91	$ 0.29
Discontinued operations (in dollars per share)						$ (0.02)	$ (0.29)	$ (0.01)		$ (0.33)	$ (0.04)
Net income (in dollars per share)	$ 0.10	$ 0.40	$ 0.39	$ 0.14	$ (0.09)	$ 0.35	$ 0.14	$ 0.19	$ 1.04	$ 0.58	$ 0.25
Net earnings (loss) per share - diluted:
Continuing operations (in dollars per share)	$ 0.10	$ 0.40	$ 0.39	$ 0.14	$ (0.09)	$ 0.37	$ 0.42	$ 0.20	$ 1.04	$ 0.90	$ 0.29
Discontinued operations (in dollars per share)						$ (0.02)	$ (0.29)	$ (0.01)		$ (0.33)	$ (0.04)
Net income (in dollars per share)	$ 0.10	$ 0.40	$ 0.39	$ 0.14	$ (0.09)	$ 0.35	$ 0.14	$ 0.19	$ 1.04	$ 0.58	$ 0.25
Potentially dilutive securities excluded from earnings per diluted share because their effect is anti-dilutive (in shares)									1,363	1,018	1,037
Comprehensive Income
Accumulated other comprehensive income (loss), foreign currency translation adjustment, net of tax	6,800,000				14,600,000				6,800,000	14,600,000
Accumulated other comprehensive income, tax	$ 900,000				$ 900,000				$ 900,000	$ 900,000
Concentration of Credit Risk
Number of banks holding demand deposit and money market accounts of the entity									11