Lease Commitments - Lease cost and other information (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Lease Cost Components:
Amortization of ROU assets - finance leases	$ 289
Interest on lease liabilities - finance leases	44
Operating lease cost (cost resulting from lease payments)	14,266	$ 8,804
Short-term lease expense	404	494
Variable lease cost (cost excluded from lease payments)	1,081	430
Total lease cost	16,084	9,728
Supplemental Cash Flow and Other Information Related to Leases:
Finance lease - operating cash flows	42
Finance lease - financing cash flows	255
Operating lease - operating cash flows (fixed payments)	12,876	7,725
Operating lease - operating cash flows (net change asset/liability)	(9,123)	1,457
New ROU assets - operating leases	43,583	$ 10,239
New ROU assets - finance leases	$ 5,374
Weighted - average remaining lease term (years) - finance leases	7 years 4 months 24 days
Weighted - average remaining lease term (years) - Operating leases	11 years 6 months 3 days	14 years 1 month 20 days
Weighted - average discount rate - finance leases	1.70%
Weighted - average discount rate - Operating leases	3.30%	3.90%
Maturity Analysis of Lease Liabilities:
2021	$ 15,753
2022	14,508
2023	13,482
2024	12,212
2025	10,747
Thereafter	78,711
Total undiscounted cash flows	145,413
Discount on cash flows	(27,092)
Total operating lease liabilities	$ 118,321	$ 88,800

The amount of increase (decrease) in operating cash flows due to change in assets and liabilities.

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Amount of right-of-use assets obtained during the period.

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Amount of interest expense on finance lease liability.

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Amount of interest paid on finance lease liability.

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Amount of cash outflow for principal payment on finance lease.

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Amount of amortization expense attributable to right-of-use asset from finance lease.

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Weighted average discount rate for finance lease calculated at point in time.

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Weighted average remaining lease term for finance lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of lease cost recognized by lessee for lease contract.

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Amount of lessee's undiscounted obligation for lease payment for operating lease.

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Amount of lessee's undiscounted obligation for lease payment for operating lease due after fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in next fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in fifth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in fourth fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in third fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payment for operating lease to be paid in second fiscal year following current fiscal year. Excludes interim and annual periods when interim periods are reported from current statement of financial position date (rolling approach).

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Amount of lessee's undiscounted obligation for lease payments in excess of discounted obligation for lease payments for operating lease.

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Amount of single lease cost, calculated by allocation of remaining cost of lease over remaining lease term. Includes, but is not limited to, single lease cost, after impairment of right-of-use asset, calculated by amortization of remaining right-of-use asset and accretion of lease liability.

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Present value of lessee's discounted obligation for lease payments from operating lease.

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Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.

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Weighted average discount rate for operating lease calculated at point in time.

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Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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Amount of increase in right-of-use asset obtained in exchange for finance lease liability.

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Amount of short-term lease cost, excluding expense for lease with term of one month or less.

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Amount of variable lease cost, excluded from lease liability, recognized when obligation for payment is incurred for finance and operating leases.

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