Fair Value Disclosure (Details Textual) (USD $)	12 Months Ended
	Dec. 31, 2012 Instrument	Dec. 31, 2011 Instrument
Fair Value Disclosure (Textual) [Abstract]
Aggregate fair value of all derivative instruments with Net liability position	$ 3,400,000
Fair Value Hedging [Member]
Fair Value Disclosure (Textual) [Abstract]
Number of instruments, outstanding	1	3
Aggregate notional amount of outstanding Fair value hedge derivative instruments	100,000,000	350,000,000
Maturity date range of hedge derivatives	2015
Cash Flow Hedges [Member]
Fair Value Disclosure (Textual) [Abstract]
Number of instruments, outstanding	12	11
Maturity date range of hedge derivatives	2013-2019
Aggregate notional amount of outstanding Cash flow hedge derivative instruments	129,200,000	73,400,000
Cash Flow Hedge Pre Tax Gain Loss to be Reclassified within Twelve Months	6,800,000
Expected After tax reclassification of net losses from accumulated other comprehensive income to earnings in Next Twelve Months	$ (4,300,000)