Fair Value - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Assets
Securities available-for-sale	$ 369,999	$ 385,079
Securities held-to-maturity	205,810	109,821
Carrying amount
Assets
Cash and cash equivalents	344,392	344,092
Securities available-for-sale	369,999	385,079
Securities held-to-maturity	202,404	109,311
Loans (including loans held-for-sale), net	1,436,885	1,347,087
FHLB and FRB stock and other investments	15,196	12,694
Accrued interest receivable	6,708	5,924
I/O strips receivables	1,101	1,367
Liabilities
Time deposits	234,293	244,861
Other deposits	1,984,341	1,817,914
Short-term borrowings		3,000
Accrued interest payable	187	170
Carried at fair value
Assets
Cash and cash equivalents	344,392	344,092
Securities available-for-sale	369,999	385,079
Securities held-to-maturity	205,810	109,821
Loans (including loans held-for-sale), net	1,506,236	1,345,236
Accrued interest receivable	6,708	5,924
I/O strips receivables	1,101	1,367
Liabilities
Time deposits	234,647	245,279
Other deposits	1,984,341	1,817,914
Short-term borrowings		3,000
Accrued interest payable	187	170
Carried at fair value | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Cash and cash equivalents	344,392	344,092
Securities available-for-sale		30,003
Accrued interest receivable		14
Carried at fair value | Significant Other Observable Inputs (Level 2)
Assets
Securities available-for-sale	369,999	355,076
Securities held-to-maturity	205,810	109,821
Loans (including loans held-for-sale), net	6,741	7,297
Accrued interest receivable	2,118	1,640
I/O strips receivables	1,101	1,367
Liabilities
Time deposits	234,647	245,279
Other deposits	1,984,341	1,817,914
Short-term borrowings		3,000
Accrued interest payable	187	170
Carried at fair value | Significant Unobservable Inputs (Level 3)
Assets
Loans (including loans held-for-sale), net	1,499,495	1,337,939
Accrued interest receivable	$ 4,590	$ 4,270