Securities - Unrealized Loss Positions (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) security	Dec. 31, 2016 USD ($) security
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	26	44
Greater than 12 months in an unrealized loss position | security	29	34
Total | security	55	78
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 3,215	$ 5,143
Greater than 12 months in an unrealized loss position	11,821	9,463
Total	15,036	14,606
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	142,402	216,050
Greater than 12 months in an unrealized loss position	245,409	213,060
Total	$ 387,811	$ 429,110
Securities Held-to-Maturity, Number of Securities
Less than 12 months in an unrealized loss position | security	8
Greater than 12 months in an unrealized loss position | security	2
Total | security	10
Securities Held-to-Maturity, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 505
Greater than 12 months in an unrealized loss position	460
Total	965
Securities Held-to-Maturity, Fair Value
Less than 12 months in an unrealized loss position	40,307
Greater than 12 months in an unrealized loss position	33,842
Total	$ 74,149
U.S. Treasury
Securities Available-for-Sale, Number of Securities
Greater than 12 months in an unrealized loss position | security	1
Total | security	1
Securities Available-for-Sale, Unrealized Losses
Greater than 12 months in an unrealized loss position	$ 127
Total	127
Securities Available-for-Sale, Fair Value
Greater than 12 months in an unrealized loss position	1,556
Total	$ 1,556
U.S. government agencies
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	1
Total | security	1
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 44
Total	44
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	1,996
Total	$ 1,996
U.S. government agency mortgage-backed
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security		11
Greater than 12 months in an unrealized loss position | security		1
Total | security		12
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position		$ 957
Greater than 12 months in an unrealized loss position		20
Total		977
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position		40,636
Greater than 12 months in an unrealized loss position		898
Total		$ 41,534
States and political subdivisions
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	2	12
Greater than 12 months in an unrealized loss position | security	1
Total | security	3	12
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 19	$ 273
Greater than 12 months in an unrealized loss position	81
Total	100	273
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	1,541	35,241
Greater than 12 months in an unrealized loss position	1,713
Total	$ 3,254	$ 35,241
Corporate bonds
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	5	1
Greater than 12 months in an unrealized loss position | security	3	2
Total | security	8	3
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 292	$ 183
Greater than 12 months in an unrealized loss position	465	153
Total	757	336
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	14,866	4,817
Greater than 12 months in an unrealized loss position	14,534	5,328
Total	$ 29,400	$ 10,145
Collateralized mortgage obligations
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	4	16
Greater than 12 months in an unrealized loss position | security	7	7
Total | security	11	23
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 334	$ 3,402
Greater than 12 months in an unrealized loss position	1,513	397
Total	1,847	3,799
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	16,218	117,752
Greater than 12 months in an unrealized loss position	43,618	18,109
Total	$ 59,836	$ 135,861
Securities Held-to-Maturity, Number of Securities
Less than 12 months in an unrealized loss position | security	8
Greater than 12 months in an unrealized loss position | security	2
Total | security	10
Securities Held-to-Maturity, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 505
Greater than 12 months in an unrealized loss position	460
Total	965
Securities Held-to-Maturity, Fair Value
Less than 12 months in an unrealized loss position	40,307
Greater than 12 months in an unrealized loss position	33,842
Total	$ 74,149
Asset-backed securities
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	9	4
Greater than 12 months in an unrealized loss position | security	8	12
Total | security	17	16
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 2,080	$ 328
Greater than 12 months in an unrealized loss position	7,958	7,997
Total	10,038	8,325
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	78,301	17,604
Greater than 12 months in an unrealized loss position	121,217	107,112
Total	$ 199,518	$ 124,716
Collateralized loan obligations
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	5
Greater than 12 months in an unrealized loss position | security	9	12
Total | security	14	12
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 446
Greater than 12 months in an unrealized loss position	1,677	$ 896
Total	2,123	896
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	29,480
Greater than 12 months in an unrealized loss position	62,771	81,613
Total	$ 92,251	$ 81,613