Retirement Plan (Tables)

6 Months Ended

Jun. 30, 2012

Retirement Plan [Abstract]

Net periodic defined benefit pension expense

	Three Months Ended						Six Months Ended
	June 30, 2012			June 30, 2011			June 30, 2012			June 30, 2011
Service cost	$	667		$	545		$	1,333		$	1,090
Interest cost		554			563			1,109			1,125
Expected return on plan assets		(591	)		(560	)		(1,181	)		(1,120	)
Amortization of prior service cost		654			244			814			488
Net periodic benefit expense	$	1,284		$	792		$	2,075		$	1,583