Derivative Instruments (Details 1) (Interest Rate Swap, USD $) In Thousands, unless otherwise specified	Mar. 31, 2013
Summary of interest rate swaps with a third party
Contractual Amount	$ 30,000
Rate (LIBOR)	1.05%
Effective Interest Rate	3.55%	[1]
Minimum
Summary of interest rate swaps with a third party
Term	Dec. 31, 2012
Maximum
Summary of interest rate swaps with a third party
Term	Sep. 30, 2016

[1] In accordance with its credit facility, the Company pays interest amounts based upon the Eurodollar LIBOR rate or Prime rate and plus a spread ranging from 0.75% to 2.75% depending on its outstanding borrowings. The effective rate shown reflects the interest rate based on the outstanding borrowings at March 31, 2013.