Leases (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Operating Leased Assets [Line Items]
Rent expense under operating lease	$ 13,553	$ 14,376	$ 13,325
Longest lease expiration date	Sep. 30, 2023
Gross rents [Abstract]
2014	14,127
2015	9,844
2016	7,630
2017	5,474
2018	2,903
Thereafter	4,455
Gross rents, Total	44,433
Operating Leases Subleases [Abstract]
2014	(1,418)
2015	(641)
2016	(609)
2017	(429)
2018	(179)
Thereafter	0
Operating Leases Subleases, Total	(3,276)
Net rents [Abstract]
2014	12,709
2015	9,203
2016	7,021
2017	5,045
2018	2,724
Thereafter	4,455
Net rents, Total	41,157
Land and buildings [Member]
Operating Leased Assets [Line Items]
Rent expense under operating lease	$ 585	$ 585	$ 583