Comprehensive income (Details 1) (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Accumulated other comprehensive income (loss), net consisted of unrealized gains (losses)
Beginning Balance			$ (356,441)	$ (205,220)
Net gain (loss) during period	53,409	(31,248)	78,592	(23,549)
Ending Balance	(277,849)	(228,769)	(277,849)	(228,769)
Cash flow hedges [Member]
Accumulated other comprehensive income (loss), net consisted of unrealized gains (losses)
Beginning Balance			112	393
Net gain (loss) during period			(112)	(141)
Ending Balance	0	252	0	252
Defined benefit plans [Member]
Accumulated other comprehensive income (loss), net consisted of unrealized gains (losses)
Beginning Balance			(277,716)	(120,892)
Net gain (loss) during period			9,464	4,288
Ending Balance	(268,252)	(116,604)	(268,252)	(116,604)
Accumulated Translation Adjustment [Member]
Accumulated other comprehensive income (loss), net consisted of unrealized gains (losses)
Beginning Balance			(803)	0
Net gain (loss) during period			(131)	196
Ending Balance	(934)	196	(934)	196
Investment securities with OTTI [Member]
Accumulated other comprehensive income (loss), net consisted of unrealized gains (losses)
Beginning Balance			(84,029)	(87,053)
Net gain (loss) during period			11,108	11,663
Ending Balance	(72,921)	(75,390)	(72,921)	(75,390)
Investment securities all other [Member]
Accumulated other comprehensive income (loss), net consisted of unrealized gains (losses)
Beginning Balance			5,995	2,332
Net gain (loss) during period			58,263	(39,555)
Ending Balance	$ 64,258	$ (37,223)	$ 64,258	$ (37,223)