Loans and Allowance for Loan Losses - Purchased Credit-Impaired Loans (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Nov. 29, 2013
PCI Loans, Fair Value [Abstract]
Contractually required payments including interest, Purchased credit-impaired loans				$ 5,706
Contractually required payments including interest, Other purchased loans				211,769
Contractually required payments including interest, Total				217,475
Less: nonaccretable difference, Purchased credit-impaired loans				(1,183)
Less: nonaccretable difference, Other purchased loans				0
Less: nonaccretable difference, Total				(1,183)
Cash flows expected to be collected (undiscounted), Purchased credit-impaired loans				4,523
Cash flows expected to be collected (undiscounted), Other purchased loans				211,769
Cash flows expected to be collected (undiscounted), Total				216,292
Accretable yield, Purchased credit-impaired loans				(707)
Accretable Yield, Other Purchased Loans				(41,826)
Accretable Yield, Total				(42,533)
Fair value of purchased credit-impaired loans				3,816
Fair value of other purchased loans				169,943
Fair value of purchased loans				173,759
Increase of specific allowance for PCI loan losses	$ 4	$ 3	$ 203
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	4,977	7,678		4,993
Carrying value	3,681	5,192		3,816
Accretable Yield [Roll Forward]
Balance at beginning of period	4,027	3,649	3,960
Additions	0	0	707
Removals	(914)	(273)	(793)
Accretion	(495)	(613)	(725)
Reclassifications (to)/from nonaccretable difference	0	1,264	500
Balance at end of period	2,618	4,027	3,649
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Allowance for Loan Losses, Decreases	2	238	$ 237
Other purchased loans
PCI Loans, Fair Value [Abstract]
Difference between the contractual principal amounts due and the fair value				6,600
Contractual interest to be earned over the life of the loans				35,200
Residential loans \| Home equity
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	224	232		239
Carrying value	68	67		69
Commercial loans \| Commercial
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	237	479		847
Carrying value	175	324		369
Commercial real estate loans
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	4,329	6,831		3,757
Carrying value	3,437	4,790		3,362
Commercial real estate loans \| Construction
PCI Loans, Carrying Value [Abstract]
Unpaid principal balance	187	136		150
Carrying value	$ 1	$ 11		$ 16

Certain Loans Acquired in Transfer, Accretable Yield, Contractual Interest

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Certain Loans Acquired in Transfer, Accretable Yield, Discount Caused by Difference in Fair Value and Contractually Required Payments

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Other Purchased Loans, Accretable Yield

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Other Purchased Loans, Acquired During Period, at Acquisition, at Fair Value

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Other Purchased Loans, Acquired During Period, Cash Flows Expected to be Collected at Acquisition

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Other Purchased Loans, Acquired During Period, Contractually Required Payments Receivable at Acquisition

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Other Purchased Loans, Nonaccretable Difference

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Purchased Credit-impaired Loans and Other Purchased Loans, Accretable Yield

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Amount of cash flows expected to be collected at acquisition of acquired loans accounted for as debt securities with evidence of deterioration of credit quality.

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The aggregate excess of a loan's cash flows expected to be collected over the investor's initial investment in the loan. This relates to loans with deteriorating of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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Amount of the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

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Amount of additions to the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

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Amount of reduction, resulting from a sale or transfer of a loan, in the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

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Amount of increase of reclassification from nonaccretable difference to the excess of a loan's cash flows expected to be collected over the investor's initial investment in acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

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Fair value at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.

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Amount of reduction in the reserve for loans impairments as a result of current information and events which result in it being probable that estimated cash flows will be significantly higher than previously expected or because actual cash flows are significantly greater than cash flows previously expected for loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that was acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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The recorded balance, net of any applicable reductions (for example, unamortized accretable yield and allowance for loan losses). This relates to loans not accounted for debt securities with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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The undiscounted sum of all amounts, including amounts deemed principal, interest, fees, penalties, and other under the loan, owed to the investor at the reporting date, whether or not currently due and whether or not any such amounts have been written or charged off by the investor. This relates to loans not accounted for as debt securities, with evidence of deterioration of credit quality since origination that were acquired by completion of a transfer for which it is probable, at acquisition, that the investor will be unable to collect all contractually required payments receivable.

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Amount of expense related to loan loss not accounted for as debt securities, with evidence of deterioration of credit quality.

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