Treasury Stock (Details) (USD $) In Thousands, except Share data, unless otherwise specified			1 Months Ended	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012	Aug. 31, 2012 August 2012 Program [Member]	Mar. 31, 2013 August 2012 Program [Member]
Treasury Stock (Textual) [Abstract]
Shares repurchased				105,264
Shares repurchased, Per Share			$ 13
Authorization Expiration			The authorization has no expiration
Shares repurchased under Board of Directors authorized program			1,000,000
Treasury Stock (Additional Textual) [Abstract]
Cost of common stock held in treasury (2013 - 21,935,218 and 2012 - 21,829,954 shares)	$ (312,006)	$ (310,958)
Common stock held in treasury, shares	21,935,218	21,829,954
Approximate shares available for future issuances	8,100,000