Defined Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Components of net periodic benefit cost included in employee compensation and benefits
Service cost	$ 0	$ 0
Interest cost	51	53
Expected return on plan assets	(63)	(57)
Amortization of (loss) / gain	0	0
Amortization of prior service cost	5	5
Effect of curtailment	0	0
Effect of special termination benefits	0	0
Effect of settlement	0	(2)
Net periodic benefit cost	$ (7)	$ (1)