Income Taxes - Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Federal
Current expense, federal	$ 10,164	$ 9,136	$ 5,677
Tax credits/true-up, federal	(3,633)	(5,841)	(5,573)
Change in deferred expense/(benefit), federal	1,787	3,730	1,700
Income tax expense, federal	8,318	7,025	1,804
State
Current expense, state	2,936	2,426	1,662
Tax credits/true-up, state	(30)	(175)	(383)
Change in deferred expense/(benefit), state	84	(32)	542
Income tax expense, state	2,990	2,219	1,821
Current expense, total	13,100	11,562	7,339
Tax credits/true-up, total	(3,663)	(6,016)	(5,956)
Change in deferred expense/(benefit), total	1,871	3,698	2,242
Total provision	$ 11,308	$ 9,244	$ 3,625