Fair Value Measurements - By Level of Valuation Inputs (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financial assets:
Cash and due from banks	$ 439,511	$ 166,097
Federal funds sold		609
Securities held to maturity	90,133	47,683
Portfolio loans, net	3,824,510	3,831,105
Financial liabilities:
Short-term borrowings		75,000
Junior subordinated debt owed to unconsolidated trusts	70,903	70,868
Level 1 | Carrying Amount
Financial assets:
Cash and due from banks	439,511	166,097
Federal funds sold		609
Level 1 | Fair Value
Financial assets:
Cash and due from banks	439,511	166,097
Federal funds sold		609
Level 2 | Carrying Amount
Financial assets:
Securities held to maturity	89,660	47,820
Accrued interest receivable	14,751	15,562
Financial liabilities:
Deposits	4,485,543	4,374,298
Securities sold under agreements to repurchase	163,081	189,157
Short-term borrowings		75,000
Long-term debt	80,000	80,000
Junior subordinated debt owed to unconsolidated trusts	70,903	70,868
Accrued interest payable	893	987
Level 2 | Fair Value
Financial assets:
Securities held to maturity	90,133	47,683
Accrued interest receivable	14,751	15,562
Financial liabilities:
Deposits	4,474,773	4,368,891
Securities sold under agreements to repurchase	163,081	189,157
Short-term borrowings		75,000
Long-term debt	80,000	80,000
Junior subordinated debt owed to unconsolidated trusts	70,903	70,868
Accrued interest payable	893	987
Level 3 | Carrying Amount
Financial assets:
Portfolio loans, net	3,824,510	3,831,105
Mortgage servicing rights	2,830	3,074
Level 3 | Fair Value
Financial assets:
Portfolio loans, net	3,827,155	3,841,760
Mortgage servicing rights	$ 9,155	$ 7,803