Stock Compensation (Stock Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2011	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Outstanding (in shares)	3,932,912.000	3,627,006.000	3,643,316
Granted (in shares)	406,875	427,219	448,580
Exercised (in shares)	(33,501)	(121,308)	(464,877)
Canceled (in shares)	(6)	(5)	(13)
Outstanding (in shares)	4,306,280	3,932,912.000	3,627,006.000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Outstanding, Weighted Average Exercise Price (in dollars per share)	$ 13.16	$ 12.16	$ 11.41
Granted, Weighted Average Exercise Price (in dollars per share)	22.13	20.95	16.97
Exercised, Weighted Average Exercise Price (in dollars per share)	11.87	11.45	10.87
Cancelled, Weighted Average Exercise Price (in dollars per share)	$ 0.00	0.00	0.00
Outstanding, Weighted Average Exercise Price (in dollars per share)		$ 13.16	$ 12.16
Outstanding, Weighted Average Remaining Contractual Term		5 years 10 months 24 days	6 years 4 months 24 days	6 years 6 months 18 days
Outstanding, Aggregate Intrinsic Value	$ 37,557	$ 36,612	$ 25,977		$ 9,959
Options exercisable (in shares)	2,111,985	2,137,112	1,678,829
Common stock fair value	$ 22.74	$ 22.47	$ 19.33