General and Summary of Significant Accounting Policies Net Income Per Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net Income	$ 7,372	$ 6,428	$ 5,878	$ 6,657	$ 13,332	$ 11,034	$ 7,367	$ 8,685	$ 26,335	$ 40,418	$ 41,281
NET INCOME PER SHARE
Weighted average number of common shares outstanding (basic)									15,282,000	14,688,000	14,223,000
Dilutive securities									365,000	586,000	502,000
Weighted Average common and common equivalent shares outstandding (diluted)									15,647,000	15,274,000	14,725,000
EPS - basic	$ 0.48	$ 0.42	$ 0.39	$ 0.44	$ 0.89	$ 0.75	$ 0.50	$ 0.60	$ 1.72	$ 2.75	$ 2.90
EPS - diluted	$ 0.46	$ 0.42	$ 0.38	$ 0.43	$ 0.86	$ 0.72	$ 0.48	$ 0.58	$ 1.68	$ 2.65	$ 2.80
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount									16,000	10,000	7,000