General and Summary of Significant Accounting Policies Net Income Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net Income	$ 5,463	$ 16,266	$ 13,570	$ 9,686	$ 7,372	$ 6,428	$ 5,878	$ 6,657	$ 44,985	$ 26,335	$ 40,418
NET INCOME PER SHARE
Weighted average number of common shares outstanding (basic)									15,848,000	15,282,000	14,688,000
Dilutive securities									648,000	365,000	586,000
Weighted Average common and common equivalent shares outstandding (diluted)									16,496,000	15,647,000	15,274,000
EPS - basic	$ 0.34	$ 1.02	$ 0.86	$ 0.62	$ 0.48	$ 0.42	$ 0.39	$ 0.44	$ 2.84	$ 1.72	$ 2.75
EPS - diluted	$ 0.33	$ 0.98	$ 0.83	$ 0.60	$ 0.46	$ 0.42	$ 0.38	$ 0.43	$ 2.73	$ 1.68	$ 2.65
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount									0	16,000	10,000