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Fair Value Measurements - Changes in Level 3 (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Collateralized loan obligations
Changes in Level 3
Beginning balance	$ 3,119
Total gains or losses
Included in other comprehensive income	16
Purchases, issuances, sales, and settlements
Settlements	(304)
Ending balance	2,844
Changes in Level 3 (liabilities)
Included in earnings (or changes in net assets)	13
States and political subdivisions
Changes in Level 3
Beginning balance	22,226	$ 111
Total gains or losses
Included in other comprehensive income	(8)
Purchases, issuances, sales, and settlements
Purchases	9,561
Settlements	(114)
Ending balance	31,665	111
Mortgage servicing rights
Changes in Level 3
Beginning balance	6,489	5,847
Total gains or losses
Included in earnings (or changes in net assets)		(906)
Purchases, issuances, sales, and settlements
Issuances	252	246
Settlements	(100)	(135)
Ending balance	6,608	$ 5,052
Changes in Level 3 (liabilities)
Included in earnings (or changes in net assets)	$ (33)

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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.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
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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 settlement 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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Fair value 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 gain (loss) recognized on the income statement for financial instrument classified as a liability measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

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