Equity (Schedule of Stock Option Activity) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Shares
Shares under option - beginning of year	716,235	823,275	807,620
Options granted	136,350	128,850	118,900
Options exercised	(204,240)	(226,160)	(95,625)
Options cancelled	(4,750)	(9,730)	(7,620)
Shares under option - end of year	643,595	716,235	823,275
Weighted Average Exercise Price
Shares under option - beginning of year	$ 14.41	$ 13.20	$ 12.78
Options granted	$ 34.84	$ 19.25	$ 15.66
Options exercised	$ 11.68	$ 12.72	$ 12.66
Options cancelled	$ 17.47	$ 15.37	$ 14.37
Shares under option - end of year	$ 19.58	$ 14.41	$ 13.20