Goodwill and Other Intangible Assets - Other Intangible Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, amortizing intangible assets	$ 125,440	$ 112,854
Accumulated amortization, amortizing intangible assets	86,888	79,522
Net carrying amount, amortizing intangible assets	38,552	33,332
Gross carrying amount, non-amortizing intangible assets	130,540	117,954
Accumulated amortization, non-amortizing intangible assets	43,652	38,432
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, non-amortizing intangible assets	5,100	5,100
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, amortizing intangible assets	110,502	99,613
Accumulated amortization, amortizing intangible assets	82,343	76,808
Net carrying amount, amortizing intangible assets	28,159	22,805
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, amortizing intangible assets	11,401	9,855
Accumulated amortization, amortizing intangible assets	2,108	653
Net carrying amount, amortizing intangible assets	9,293	9,202
Acquired software
Finite-Lived Intangible Assets [Line Items]
Gross carrying amount, amortizing intangible assets	3,537	3,386
Accumulated amortization, amortizing intangible assets	2,437	2,061
Net carrying amount, amortizing intangible assets	$ 1,100	$ 1,325