Deferred tax reconciliation (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in net deferred income tax liability from the preceding table	$ 102,002
Deferred taxes associated with other comprehensive loss	(7,277)
Other	(7,947)
Deferred income tax expense for the period	$ 86,778	$ (7,503)	$ 118,925