Significant Accounting Policies and Basis of Presentation - Narrative (Details) - USD ($) $ in Thousands	Jan. 01, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative decrease from change in accounting principle - CECL		$ (1,007,847)	$ (964,636)	$ (1,052,795)	$ (991,405)	$ (978,373)	$ (956,816)
Deferred taxes				11,740
Available-for-sale debt securities, accrued interest		3,200
Accounting Standards Update 2016-13
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Initial allowance on loans purchased with credit deterioration	$ 200
Financing receivable, purchased with credit deterioration, discount	300
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative decrease from change in accounting principle - CECL		$ (338,665)	$ (319,529)	(381,519)	$ (334,157)	$ (328,476)	$ (316,651)
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative decrease from change in accounting principle - CECL				(61,475)
Deferred taxes	(21,510)
Cumulative Effect, Period of Adoption, Adjustment | Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative decrease from change in accounting principle - CECL	$ 61,500			$ (61,475)