Shareholder's Equity (Narrative) (Details) (USD $)	0 Months Ended		12 Months Ended
	Aug. 09, 2013 M	Apr. 24, 2012 M	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Common Stock:
Stock repurchased program authorized by the board of directors	$ 40,000,000	$ 40,000,000
Period of stock repurchase program, months	18	18
Average price per share			$ 36.93	$ 28.50
Amount remaining under stock repurchase plan			27,100,000
Stock Incentive Plans:
Unrecognized compensation cost on non vested awards			7,426,000
Employee Service Share-based Compensation, Nonvested Awards			1 year 0 months 0 days
Share based payment award shares purchased for award			0	20,000	923,000
Stock Repurchased Under Repurchase Program [Member]
Common Stock:
Repurchase of common stock, shares			1,154,378	415,084
Repurchase of common stock			42,652,000	11,838,000
Stock Repurchased To Cover Employee Tax Withholdings [Member]
Common Stock:
Repurchase of common stock, shares			102,252	48,139
Repurchase of common stock			$ 3,312,000	$ 1,263,000
Outside Directors [Member]
Stock Incentive Plans:
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			1 year	1 year
Employees [Member]
Stock Incentive Plans:
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			4 years
Number of installments in restricted stock granted.			3
Options term			10
Stock Options [Member]
Stock Incentive Plans:
Number of shares authorized for grant under share incentive plan			2,760,250
Shares available for future grants/issuance under stock incentive plan			895,822
Restricted Stock [Member]
Stock Incentive Plans:
Shares available for future grants/issuance under stock incentive plan			733,718