Fair Value - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Assets
Securities available-for-sale	$ 341,590	$ 306,589
Securities held-to-maturity	336,790	318,748
I/O strips receivables	1,045	1,067
Significant Other Observable Inputs (Level 2)
Assets
I/O strips receivables	1,045	1,067
Carrying amount
Assets
Cash and cash equivalents	287,846	266,103
Securities available-for-sale	341,590	306,589
Securities held-to-maturity	341,383	324,010
Loans (including loans held-for-sale), net	1,498,063	1,489,223
FHLB and FRB stock and other investments	15,203	15,196
Accrued interest receivable	7,127	6,859
I/O strips receivables	1,045	1,067
Liabilities
Time deposits	224,953	224,717
Other deposits	2,105,134	2,037,423
Accrued interest payable	148	168
Carried at fair value
Assets
Cash and cash equivalents	287,846	266,103
Securities available-for-sale	341,590	306,589
Securities held-to-maturity	336,790	318,748
Loans (including loans held-for-sale), net	1,541,322	1,541,190
Accrued interest receivable	7,127	6,859
I/O strips receivables	1,045	1,067
Liabilities
Time deposits	225,297	225,047
Other deposits	2,105,134	2,037,423
Accrued interest payable	148	168
Carried at fair value | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets
Cash and cash equivalents	287,846	266,103
Carried at fair value | Significant Other Observable Inputs (Level 2)
Assets
Securities available-for-sale	341,590	306,589
Securities held-to-maturity	336,790	318,748
Loans (including loans held-for-sale), net	3,911	5,705
Accrued interest receivable	2,310	1,961
I/O strips receivables	1,045	1,067
Liabilities
Time deposits	225,297	225,047
Other deposits	2,105,134	2,037,423
Accrued interest payable	148	168
Carried at fair value | Significant Unobservable Inputs (Level 3)
Assets
Loans (including loans held-for-sale), net	1,537,411	1,535,485
Accrued interest receivable	$ 4,817	$ 4,898