Shareholders' Equity and Stock Compensation (Narrative) (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Shareholders Equity and Share-Based Payments [Line Items]
Share-based Compensation, Excluding Accelerated Compensation Cost	$ 2,500,000	$ 3,000,000
Stock repurchased during period	1,796,000		$ 17,708,000
Total income tax benefit recognized related to stock-based compensation	977,000	1,200,000
Total intrinsic value of options exercised	112,000	132,000
Cash received from exercise of stock options	230,000	635,000
Income tax benefits received	1,800,000	1,900,000
Employee Stock Option
Shareholders Equity and Share-Based Payments [Line Items]
Cash received from exercise of stock options	49,000	33,000
Total unrecognized compensation cost related to nonvested stock awards	$ 15,000
Expected recognized over a weighted-average period, years	4 months 24 days
Restricted Stock
Shareholders Equity and Share-Based Payments [Line Items]
Total fair value of restricted stock shares/units vested and released	$ 4,500,000	4,400,000
Total unrecognized compensation cost related to nonvested stock awards	$ 13,700,000
Expected recognized over a weighted-average period, years	1 year 11 months 27 days
Restricted Stock Units (RSUs)
Shareholders Equity and Share-Based Payments [Line Items]
Total fair value of restricted stock shares/units vested and released	$ 41,000	$ 260,000
Total unrecognized compensation cost related to nonvested stock awards	$ 1,100,000
Expected recognized over a weighted-average period, years	8 months 19 days