Taxes on Income (Earnings Before Taxes) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Taxes on Income [Abstract]
Earnings before taxes on income - United States	$ 92,805	$ 86,525	$ 77,827	$ 83,369	$ 87,279	$ 86,328	$ 68,279	$ 52,861	$ 340,526	$ 294,747	$ 189,640
Federal [Abstract]
Current									41,297	33,640	33,014
Deferred									71,767	65,451	30,643
State and local									14,843	10,164	8,601
Total provision for taxes on income	$ 34,231	$ 32,794	$ 29,392	$ 31,490	$ 30,510	$ 32,734	$ 26,050	$ 19,961	$ 127,907	$ 109,255	$ 72,258