Shareholders' Equity and Stock Compensation (Narrative) (Details) - USD ($) shares in Thousands, $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Apr. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Equity [Abstract]
Stock Repurchased During Period, Shares	327
Stock Repurchased During Period, Value	$ 8,000
Shareholders Equity and Share-Based Payments [Line Items]
Share-based Compensation, Excluding Accelerated Compensation Cost		$ 1,200	$ 1,200	$ 2,800	$ 3,700
Total income tax benefit recognized related to stock-based compensation		320	464	721	1,400
Proceeds from stock options exercised				1,016	463
Income tax benefits received		384	554	3,000	2,400
Employee Stock Option
Shareholders Equity and Share-Based Payments [Line Items]
Total intrinsic value of options exercised		213	29	871	141
Cash from stock options exercised		257	233	373	269
Proceeds from stock options exercised		257	233	1,000	463
Total unrecognized compensation cost related to nonvested stock awards		0		0
Restricted Stock
Shareholders Equity and Share-Based Payments [Line Items]
Total fair value of restricted stock shares/units vested and released		844	632	10,500	5,200
Total unrecognized compensation cost related to nonvested stock awards		13,000		$ 13,000
Expected recognized over a weighted-average period, years				1 year 9 months 26 days
Restricted Stock Units (RSUs)
Shareholders Equity and Share-Based Payments [Line Items]
Total fair value of restricted stock shares/units vested and released		449	$ 770	$ 449	$ 811
Total unrecognized compensation cost related to nonvested stock awards		$ 0		$ 0