Contingencies and Guarantees (Schedule of Changes in Repurchase Reserve) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	$ 2,625	$ 6,650	$ 2,725	$ 7,250
Net increase/(decrease) to reserve	0	363	(53)	(39)
Net realized (losses)/gains	0	(363)	(47)	(561)
Balance at end of period	2,625	6,650	2,625	6,650
Residential Mortgages
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period			2,700
Balance at end of period	$ 2,600	$ 6,700	$ 2,600	$ 6,700