Fair Value - Financial Instruments (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Assets:
Cash and due from banks	$ 150,138	$ 192,800
Interest-bearing deposits in other banks	84,898	153,770
Securities held-to-maturity	13,400	13,760
FHLB and FRB stock	80,508	69,708
Loans	10,581,920	10,342,083
Investment in BOLI	281,285	279,900
Liabilities
Deposits	11,146,022	11,053,325
Borrowed funds	950,688	714,884
Senior and subordinated debt	195,312	195,170
Carrying Amount | Level 1
Assets:
Cash and due from banks	150,138	192,800
Carrying Amount | Level 2
Assets:
Interest-bearing deposits in other banks	84,898	153,770
Securities held-to-maturity	13,400	13,760
FHLB and FRB stock	80,508	69,708
Liabilities
Deposits	11,146,022	11,053,325
Borrowed funds	950,688	714,884
Senior and subordinated debt	195,312	195,170
Accrued interest payable	4,107	4,704
Carrying Amount | Level 3
Assets:
Loans	10,584,932	10,345,397
Investment in BOLI	281,285	279,900
Accrued interest receivable	45,703	45,261
Other interest-earning assets	146	228
Fair Value | Level 1
Assets:
Cash and due from banks	150,138	192,800
Fair Value | Level 2
Assets:
Interest-bearing deposits in other banks	84,898	153,770
Securities held-to-maturity	11,287	12,013
FHLB and FRB stock	80,508	69,708
Liabilities
Deposits	11,123,916	11,038,819
Borrowed funds	950,688	714,884
Senior and subordinated debt	194,980	198,806
Accrued interest payable	4,107	4,704
Fair Value | Level 3
Assets:
Loans	10,256,027	10,059,992
Investment in BOLI	281,285	279,900
Accrued interest receivable	45,703	45,261
Other interest-earning assets	$ 146	$ 228