Basis of Presentation (Details) $ in Thousands	Mar. 31, 2019 USD ($) lease	Jan. 01, 2019 USD ($) lease	Jan. 01, 2018
Schedule of Equity Method Investments [Line Items]
Lease Liabilities	$ 1,235
Operating lease, liabilities	40,225
Financing lease, right-of-use assets	1,213
Operating lease, right-of-use assets	$ 35,686
Number of operating lease agreements | lease	42
ASU No. 2016-02
Schedule of Equity Method Investments [Line Items]
Lease Liabilities		$ 1,200
Operating lease, liabilities		33,700
Financing lease, right-of-use assets		1,200
Operating lease, right-of-use assets		$ 33,400
Number of operating lease agreements | lease		1
New Partnership
Schedule of Equity Method Investments [Line Items]
Equity method investment, ownership percentage			30.00%
S&T Evergreen Insurance LLC | Subsidiaries
Schedule of Equity Method Investments [Line Items]
Percentage of ownership in subsidiary sold			70.00%