Loans Receivable, Net - ACL Activity (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Allowance for credit losses
Balance at beginning of period	$ 151,448	$ 162,509	$ 158,243	$ 124,490
Impact of adopting CECL				3,720
Acquisitions				49
Provision for credit losses	2,313	2,869	(2,921)	39,165
Charge-offs	(2,620)	(2,630)	(8,566)	(7,865)
Recoveries	2,468	1,804	6,853	4,993
Balance at end of period	153,609	164,552	153,609	164,552
Residential real estate
Allowance for credit losses
Balance at beginning of period	10,143	9,986	9,604	10,111
Impact of adopting CECL				3,584
Acquisitions				0
Provision for credit losses	1,703	(216)	2,005	(3,923)
Charge-offs	0	0	(38)	(21)
Recoveries	13	35	288	54
Balance at end of period	11,859	9,805	11,859	9,805
Commercial real estate
Allowance for credit losses
Balance at beginning of period	96,597	89,104	86,999	69,496
Impact of adopting CECL				10,533
Acquisitions				49
Provision for credit losses	2,931	5,208	11,663	14,084
Charge-offs	(162)	(445)	(203)	(625)
Recoveries	672	530	1,579	860
Balance at end of period	100,038	94,397	100,038	94,397
Other commercial
Allowance for credit losses
Balance at beginning of period	31,983	48,838	49,133	36,129
Impact of adopting CECL				(13,759)
Acquisitions				0
Provision for credit losses	(3,321)	1,199	(18,905)	28,358
Charge-offs	(677)	(1,598)	(3,790)	(3,471)
Recoveries	860	314	2,407	1,496
Balance at end of period	28,845	48,753	28,845	48,753
Home equity
Allowance for credit losses
Balance at beginning of period	7,837	9,962	8,182	4,937
Impact of adopting CECL				3,400
Acquisitions
Provision for credit losses	(124)	(2,526)	(491)	(860)
Charge-offs	0	(99)	(45)	(293)
Recoveries	152	93	219	246
Balance at end of period	7,865	7,430	7,865	7,430
Other consumer
Allowance for credit losses
Balance at beginning of period	4,888	4,619	4,325	3,817
Impact of adopting CECL				(38)
Acquisitions				0
Provision for credit losses	1,124	(796)	2,807	1,506
Charge-offs	(1,781)	(488)	(4,490)	(3,455)
Recoveries	771	832	2,360	2,337
Balance at end of period	$ 5,002	$ 4,167	$ 5,002	$ 4,167