Pension Plan (Tables)

6 Months Ended

Jun. 30, 2013

Compensation and Retirement Disclosure [Abstract]

Schedule of net benefit cost

Net periodic pension costs consist of the following: 

	Three Months Ended June 30,						Six Months Ended June 30,
	2012			2013			2012			2013
Service cost	$	65		$	69		$	130		$	138
Interest cost on projected benefit obligation	860			785			1,719			1,571
Expected return on plan assets	(1,131		)	(1,302		)	(2,262		)	(2,604		)
Net amortization and deferral	731			732			1,463			1,463
Net periodic pension cost	$	525		$	284		$	1,050		$	568