Fair Value Measurements - Carrying Values and Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Securities available-for-sale, at fair value	$ 693,487	$ 660,963
FHLB and other restricted stock	31,817	23,032
LIABILITIES
Junior subordinated debt securities	45,619	45,619	$ 45,619
Carrying Value
ASSETS
Cash and due from banks, including interest-bearing deposits	139,486	99,399
Securities available-for-sale, at fair value	693,487	660,963
Loans held for sale	3,793	35,321
Portfolio loans, net of unearned income	5,611,419	5,027,612
Bank owned life insurance	72,081	70,175
FHLB and other restricted stock	31,817	23,032
Trading securities held in a Rabbi Trust	4,410	4,021
Mortgage servicing rights	3,744	3,237
LIABILITIES
Deposits	5,272,377	4,876,611
Securities sold under repurchase agreements	50,832	62,086
Short-term borrowings	660,000	356,000
Long-term borrowings	14,713	117,043
Junior subordinated debt securities	45,619	45,619
Carrying Value | Interest Rate Swap
ASSETS
Derivative financial assets	6,960	11,295
LIABILITIES
Derivative financial liabilities	6,958	11,276
Carrying Value | Interest Rate Lock Commitments
ASSETS
Derivative financial assets	236	261
Carrying Value | Forward Sale Contracts
LIABILITIES
Derivative financial liabilities	27	5
Fair Value Measurements
ASSETS
Cash and due from banks, including interest-bearing deposits	139,486	99,399
Securities available-for-sale, at fair value	693,487	660,963
Loans held for sale	3,815	35,500
Portfolio loans, net of unearned income	5,551,266	5,001,004
Bank owned life insurance	72,081	70,175
FHLB and other restricted stock	31,817	23,032
Trading securities held in a Rabbi Trust	4,410	4,021
Mortgage servicing rights	4,098	3,396
LIABILITIES
Deposits	5,276,499	4,881,718
Securities sold under repurchase agreements	50,832	62,086
Short-term borrowings	660,000	356,000
Long-term borrowings	15,267	117,859
Junior subordinated debt securities	45,619	45,619
Fair Value Measurements | Interest Rate Swap
ASSETS
Derivative financial assets	6,960	11,295
LIABILITIES
Derivative financial liabilities	6,958	11,276
Fair Value Measurements | Interest Rate Lock Commitments
ASSETS
Derivative financial assets	236	261
Fair Value Measurements | Forward Sale Contracts
LIABILITIES
Derivative financial liabilities	27	5
Fair Value Measurements | Level 1
ASSETS
Cash and due from banks, including interest-bearing deposits	139,486	99,399
Trading securities held in a Rabbi Trust	4,410	4,021
Fair Value Measurements | Level 2
ASSETS
Securities available-for-sale, at fair value	693,487	660,963
Bank owned life insurance	72,081	70,175
Fair Value Measurements | Level 2 | Interest Rate Swap
ASSETS
Derivative financial assets	6,960	11,295
LIABILITIES
Derivative financial liabilities	6,958	11,276
Fair Value Measurements | Level 2 | Interest Rate Lock Commitments
ASSETS
Derivative financial assets	236	261
Fair Value Measurements | Level 2 | Forward Sale Contracts
LIABILITIES
Derivative financial liabilities	27	5
Fair Value Measurements | Level 3
ASSETS
Loans held for sale	3,815	35,500
Portfolio loans, net of unearned income	5,551,266	5,001,004
FHLB and other restricted stock	31,817	23,032
Mortgage servicing rights	4,098	3,396
LIABILITIES
Deposits	5,276,499	4,881,718
Securities sold under repurchase agreements	50,832	62,086
Short-term borrowings	660,000	356,000
Long-term borrowings	15,267	117,859
Junior subordinated debt securities	$ 45,619	$ 45,619