Basis of Presentation - Recently Adopted Accounting Pronouncements (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate2016-13Member	us-gaap:AccountingStandardsUpdate2016-13Member
Stockholders' equity	$ 1,476,434	$ 1,153,119	$ 1,409,834	$ 1,137,295	$ 1,127,163	$ 1,039,358
Financing receivable, allowance for credit loss, period increase (decrease)	(475)
Debt securities, held-to-maturity, allowance for credit loss, period increase (decrease)	1,300
Decrease in off-balance sheet credit exposure	788
Purchased credit impaired (“PCI”) loans		13,300
Financing receivable, allowance for credit losses, effect of change in method	$ 3,200
Cumulative Effect, Period Of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Stockholders' equity		$ (4)