Other Investments - Mortgage Servicing Rights (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period			$ 286,778
Additions			868	$ 0
Changes in fair value due to:
Balance at End of Period	$ 204,946		204,946
Mortgage servicing rights
Servicing Asset at Fair Value, Amount [Roll Forward]
Balance at beginning of period	47,396	$ 64,674	60,281	63,598
Additions	0	0	868	0
Sales	0	0	0	(1,077)
Changes in fair value due to:
Changes in assumptions	(5,150)	1,099	(15,291)	6,388
Other changes	(2,409)	(1,988)	(6,021)	(5,124)
Balance at End of Period	39,837	63,785	39,837	63,785
Servicing income	3,850	4,004	11,310	11,601
Cost of sub-servicer	(319)	(324)	(1,090)	(1,254)
Net servicing fee income	3,531	3,680	10,220	10,347
Market valuation changes of MSRs	(7,489)	(823)	(21,243)	1,324
Market valuation changes of associated derivatives	4,389	(890)	13,157	(7,151)
MSR reversal of provision for repurchases	0	0	208	277
MSR Income, Net	$ 431	$ 1,967	$ 2,342	$ 4,797