Borrowing Arrangements (Details 5) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Borrowing Arrangements
Liability to make principal payments on debt outstanding in 2013	$ 61,000	$ 19,565,000
Liability to make principal payments on debt outstanding in 2016	45,700,000
Liability to make principal payments on debt outstanding in 2017	10,100,000
Liability to make principal payments on debt outstanding in 2018	$ 200,000