Other pension and compensation disclosure tables (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Amounts recognized in the consolidated balance sheets
Non-current assets	$ 0	$ 0
Current liabilities	0	0
Non-current liabilities	1,606	8,275
Amounts recognized in accumulated other comprehensive income (loss)
Net loss	(8,212)	(13,975)
Prior service cost	0	0
Net transitional obligation	0	0
Total amount recognized in other comprehensive loss	(8,212)	(13,975)
Information about pension plans
Projected benefit obligation	24,768	27,927	24,189	20,074
Accumulated benefit obligation	24,768	27,927
Fair value of plan assets	23,162	19,652	15,547	14,457
Components of net periodic pension benefit cost
Service cost	0	0	0
Interest cost	1,200	1,154	1,062
Expected return on assets	(926)	(846)	(1,006)
Net amortization and deferrals	930	899	608
Net periodic benefit cost	1,204	1,207	664
Future benefit payments
2014	632
2015	463
2016	549
2017	657
2018	533
Next five years	3,929
Employers’ contributions	$ 2,542	$ 2,719	$ 3,023