Defined Benefit Plans (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Components of net periodic benefit cost included in employee compensation and benefits
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	53	60	159	198
Expected return on plan assets	(60)	(71)	(176)	(207)
Amortization of (loss) / gain	0	0	0	0
Amortization of prior service cost	5	5	15	15
Effect of settlement	(17)	1	(20)	(30)
Net periodic benefit cost	$ (19)	$ (5)	$ (22)	$ (24)