Accumulated Other Comprehensive Loss (Amounts Reclassified out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Unrealized losses on available-for-sale securities:
Interest expense	$ 17,010	$ 17,320	$ 51,986	$ 42,027
Other income/(expense)	284	220	2,159	(3,964)
Total reclassified out of AOCL, before tax	2,113	1,953	5,667	8,434
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Unrealized losses on available-for-sale securities:
Other income/(expense)				1,679
Interest Rate Swap [Member]
Unrealized losses on available-for-sale securities:
Total reclassified out of AOCL, before tax	480	(3)	838	(3)
Interest Rate Swap [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Unrealized losses on available-for-sale securities:
Equity in income of affiliated companies	1,633	1,952	4,730	6,754
Interest expense	$ 480	(3)	838	(3)
Interest Rate Cap/Collar [Member]
Unrealized losses on available-for-sale securities:
Total reclassified out of AOCL, before tax		4	99	4
Interest Rate Cap/Collar [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Unrealized losses on available-for-sale securities:
Interest expense		$ 4	$ 99	$ 4