Operating Leases (Details) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020 USD ($) Property	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) Property	Sep. 30, 2019 USD ($)	Dec. 31, 2019 USD ($)
Other information related to leases [Abstract]
Operating lease cost		$ 1,966	$ 2,007	$ 5,893	$ 5,828
Variable lease cost		369	497	1,524	1,472
Total Lease costs		$ 2,335	$ 2,504	7,417	7,300
Cash paid for amounts included in the measurement of lease liabilities [Abstract]
Operating cash flows from operating leases				6,022	5,824
Right-of-use assets obtained in exchange for lease obligations:				$ 287	$ 54,038
Weighted average remaining lease term		8 years 10 months 24 days	9 years 4 months 24 days	8 years 10 months 24 days	9 years 4 months 24 days
Weighted average discount rate		3.25%	3.30%	3.25%	3.30%
Future minimum lease payments under non-cancellable leases [Abstract]
2020	[1]	$ 2,020		$ 2,020
2021		8,062	$ 7,820	8,062	$ 7,820
2022		7,561	7,818	7,561	7,818
2023		7,256	7,300	7,256	7,300
2024		7,128	6,978	7,128	6,978
Thereafter		28,551		28,551
Total lease payments		60,578		60,578
Less: Interest		8,453	9,752	8,453	9,752
Present value of lease liabilities		52,125	54,731	52,125	54,731	$ 56,553
Minimum annual lease payments under terms of leases [Abstract]
2019	[2]		1,967		1,967
2020		8,062	7,820	8,062	7,820
2021		7,561	7,818	7,561	7,818
2022		7,256	7,300	7,256	7,300
2023		7,128	6,978	7,128	6,978
Thereafter			32,600		32,600
Total lease payments			64,483		64,483
Less: Interest		8,453	9,752	8,453	9,752
Present value of lease liabilities		52,125	$ 54,731	52,125	$ 54,731	$ 56,553
Director [Member]
Future minimum lease payments under non-cancellable leases [Abstract]
Total lease payments		4,700		4,700
Less: Interest		$ 699		$ 699
Number of Properties Under Lease Owned by Related Party | Property		6		6
Minimum annual lease payments under terms of leases [Abstract]
Less: Interest		$ 699		$ 699
Minimum [Member]
Leases, operating [Abstract]
Operating lease expiration term		3 months		3 months
Maximum [Member]
Leases, operating [Abstract]
Operating lease expiration term		24 years		24 years

[1] Excluding the nine months ended September 30, 2020.

[2] Excluding the nine months ended September 30, 2019.