Investments - Schedule of Unrealized Loss on Investments (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	$ 93,089	$ 255,984
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	620	1,319
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	5,198	41,491
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	81	435
Debt Securities, Available-for-sale, Unrealized Loss Position	98,287	297,475
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	701	1,754
Obligations of states and political subdivisions
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	10,475	56,327
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	205	363
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	0	0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	0	0
Debt Securities, Available-for-sale, Unrealized Loss Position	10,475	56,327
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	205	363
Agency mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months	82,614	131,693
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss	415	756
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer	5,198	41,491
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss	81	435
Debt Securities, Available-for-sale, Unrealized Loss Position	87,812	173,184
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss	$ 496	1,191
Corporate Debt Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months		67,964
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, Less than 12 Months, Accumulated Loss		200
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer		0
Debt Securities, Available-for-sale, Continuous Unrealized Loss Position, 12 Months or Longer, Accumulated Loss		0
Debt Securities, Available-for-sale, Unrealized Loss Position		67,964
Debt Securities, Available-for-sale, Unrealized Loss Position, Accumulated Loss		$ 200