Allowance for Credit Losses and Credit Quality of Loans (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Dec. 31, 2020	Mar. 31, 2021	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2019
Allowance for Credit Losses [Abstract]
Allowance for credit losses	$ 98,500	$ 110,000	$ 105,000	$ 113,500	$ 100,000	$ 75,999
Percentage of allowance of credit losses	1.31%	1.47%
Retained earnings	$ 805,722	$ 749,056
Loans purchased with credit deterioration	0	0
Accrued Interest Receivable [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses	400	600
AIR on loans	$ 20,600	23,700
Write-off of uncollectible interest period	120 days
COVID-19 [Member]
Allowance for Credit Losses [Abstract]
Loans in modification programs related to COVID-19	$ 32,300
ASU 2016-13 [Member] | Loans [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses						3,000
Retained earnings						(2,300)
Deferred tax asset						700
Consumer Loans [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses	34,881	37,803	34,580	40,094	37,546	32,122
Amount of loans purchased		$ 51,900
Discount on loans purchased		1.00%
Allowance for credit losses on loans purchased		$ 3,600
Residential [Member]
Allowance for Credit Losses [Abstract]
Allowance for credit losses	19,428	$ 21,255	$ 20,375	$ 23,020	$ 20,242	$ 16,721
Amount of loans purchased	$ 20,100
Premium on loans purchased	2.00%
Allowance for credit losses on loans purchased	$ 200