Parent Company Only Financial Information - Condensed Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Interest income									$ 15,776	$ 25,535	$ 23,022
Interest expense	$ (13,239)	$ (13,990)	$ (16,055)	$ (25,844)	$ (29,000)	$ (30,440)	$ (29,566)	$ (28,010)	(69,128)	(117,016)	(89,592)
Net loss from fair value adjustments									(2,142)	(5,353)	(4,122)
Other operating expenses									(16,635)	(14,937)	(15,235)
Total income tax provision	417	4,489	5,808	(206)	3,957	2,536	3,272	2,287	10,508	12,052	10,395
Net income	$ 3,461	$ 14,331	$ 18,272	$ (1,390)	$ 12,931	$ 10,724	$ 10,556	$ 7,068	34,674	41,279	55,090
Other comprehensive gain (loss), net of tax									(6,459)	2,945	(2,472)
Comprehensive net income									28,215	44,224	52,618
Holding Company
Dividends from the Bank									78,833	32,000	34,000
Interest income									466	250	275
Interest expense									(5,858)	(6,677)	(6,479)
Net loss from fair value adjustments									(85)	(2,725)	(4,769)
Other operating expenses									(3,975)	(2,833)	(1,391)
Income before taxes and equity in undistributed earnings of subsidiary									69,381	20,015	21,636
Total income tax provision									2,274	3,173	3,907
Income before equity in undistributed earnings of subsidiary									71,655	23,188	25,543
Equity in undistributed earnings of the Bank									(36,981)	18,091	29,547
Net income									34,674	41,279	55,090
Other comprehensive gain (loss), net of tax									(6,459)	2,945	(2,472)
Comprehensive net income									$ 28,215	$ 44,224	$ 52,618