Balance Sheet Offsetting (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Offsetting Liabilities
Gross Amounts Recognized	$ 409,411	$ 172,907
Gross Amounts Offset	0	0
Net Amounts Presented	409,411	172,907
Gross Amounts Not Offset, Financial Instruments	(14,579)	(1,214)
Gross Amounts Not Offset, Cash Collateral	(373,737)	(151,852)
Net Amount	21,095	19,841
Repurchase agreements
Offsetting Repurchase Agreement Liabilities
Gross Amounts Recognized	350,000	150,000
Gross Amounts Offset	0	0
Net Amounts Presented	350,000	150,000
Gross Amounts Not Offset, Financial Instruments	0	0
Gross Amounts Not Offset, Cash Collateral	(350,000)	(150,000)
Net Amount	0	0
Interest rate swaps
Offsetting Assets
Gross Amounts Recognized	216,340	48,642
Gross Amounts Offset	0	0
Net Amounts Presented	216,340	48,642
Gross Amounts Not Offset, Financial Instruments	(14,579)	(1,214)
Gross Amounts Not Offset, Cash Collateral	0	0
Net Amount	201,761	47,428
Offsetting Liabilities
Gross Amounts Recognized	59,411	22,907
Gross Amounts Offset	0	0
Net Amounts Presented	59,411	22,907
Gross Amounts Not Offset, Financial Instruments	(14,579)	(1,214)
Gross Amounts Not Offset, Cash Collateral	(23,737)	(1,852)
Net Amount	$ 21,095	$ 19,841