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Fair Value Measurements - Changes in Level 3 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Total gains or losses
Included in other comprehensive income	$ (82)
Purchases, issuances, sales, and settlements
Transfers into Level 3	3,201
Changes in Level 3 (liabilities)
Ending balance	3,119
Asset-backed securities
Changes in Level 3
Beginning balance		$ 52,941
Total gains or losses
Included in earnings (or changes in net assets)		(28)
Included in other comprehensive income		(541)
Purchases, issuances, sales, and settlements
Sales		(27,455)
Transfers out of Level 3	(24,917)
States and political subdivisions
Changes in Level 3
Beginning balance	111	118
Total gains or losses
Included in other comprehensive income	87
Purchases, issuances, sales, and settlements
Purchases	14,296
Settlements	(81)	(7)
Ending balance	22,226	111
Transfers into Level 3	7,813
Mortgage servicing rights
Changes in Level 3
Beginning balance	5,847	5,462
Total gains or losses
Included in earnings (or changes in net assets)	(215)	(466)
Purchases, issuances, sales, and settlements
Issuances	1,561	1,526
Settlements	(704)	(675)
Ending balance	$ 6,489	$ 5,847

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Amount of gain (loss) recognized in the income statement for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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-Section 50
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Amount of gain (loss) recognized in other comprehensive income (loss) for financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of issuances of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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Amount of transfer of financial instrument classified as an asset into level 3 of the fair value hierarchy.

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Amount of transfers of financial instrument classified as an asset out of level 3 of the fair value hierarchy.

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