General and Summary of Significant Accounting Policies Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Net Income	$ 9,512	$ 18,806	$ 16,606		$ 5,463	$ 16,266	$ 13,570	$ 9,686	$ 63,084	$ 44,985	$ 26,335
NET INCOME PER SHARE
Weighted average number of common shares outstanding (basic)									16,168	15,848	15,282
Weighted Average Number Diluted Shares Outstanding Adjustment									1,086	648	365
Weighted Average common and common equivalent shares outstandding (diluted)									17,254	16,496	15,647
Basic	$ 0.58	$ 1.16	$ 1.03	$ 0.99	$ 0.34	$ 1.02	$ 0.86	$ 0.62	$ 3.90	$ 2.84	$ 1.72
Diluted	$ 0.54	$ 1.09	$ 0.98	$ 0.96	$ 0.33	$ 0.98	$ 0.83	$ 0.60	$ 3.66	$ 2.73	$ 1.68