Parent Company Income Statement (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Expenses
Interest expense		$ 13,710	$ 15,026	$ 16,125	$ 9,018	$ 7,618	$ 6,641	$ 5,999	$ 5,278	$ 53,879	$ 25,536	$ 18,334
Income tax benefit		14,368	17,036	10,007	11,522	8,258	9,969	9,249	6,828	52,933	34,304	47,341
Net Income		$ 47,477	$ 51,845	$ 30,628	$ 35,225	$ 29,934	$ 33,015	$ 31,118	$ 27,555	165,175	121,622	87,204
Parent Company [Member]
Income
Dividend Income, Operating	[1]									181,790	71,255	47,006
Interest income (2)	[2]											50
Total income										181,790	71,255	47,056
Expenses
Interest expense										8,236	4,234	3,995
Total expenses										8,236	4,234	3,995
Income before income taxes and equity in undistributed income of subsidiaries										173,554	67,021	43,061
Income tax benefit										(2,262)	(1,151)	(1,523)
Income of parent company										175,816	68,172	44,584
Equity (deficit) in undistributed income of subsidiaries										(10,641)	53,450	42,620
Net Income										$ 165,175	$ 121,622	$ 87,204

[1] Majority of balance eliminates in consolidation.

[2] Entire balance eliminated in consolidation.