Securities - Contractural Maturities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Securities Available-for-Sale, Amortized Cost
Due in one year or less	$ 14,410
Due after one year through five years	4,575
Due after five years through ten years	16,855
Due after ten years	43,835
Debt securities excluding securities not due at a single maturity date	79,675
Total	$ 545,433	$ 470,719
Securities Available-for-Sale, Weighted Average Yield
Due in one year or less (as a percent)	1.93%
Due after one year through five years (as a percent)	3.02%
Due after five years through ten years (as a percent)	2.62%
Due after ten years (as a percent)	3.51%
Debt securities (as a percent)	3.01%
Total (as a percent)	2.70%
Securities Available-for-Sale, Fair Value
Due in one year or less	$ 14,416
Due after one year through five years	4,571
Due after five years through ten years	16,594
Due after ten years	43,752
Debt securities	79,333
Fair Value	531,838	456,066
Securities Held-to-Maturity, Amortized Cost
Amortized Cost		247,746
Securities Held-to-Maturity, Fair Value
Fair Value		251,675
Collateralized mortgage obligations
Securities Available-for-Sale, Amortized Cost
Securities not due at a single maturity date	216,863
Total	$ 174,352	68,743
Securities Available-for-Sale, Weighted Average Yield
Securities not due at a single maturity date, Weighted Average Yield (as a percent)	2.43%
Securities Available-for-Sale, Fair Value
Securities not due at a single maturity date	$ 212,461
Fair Value	170,927	66,920
Securities Held-to-Maturity, Amortized Cost
Amortized Cost		211,241
Securities Held-to-Maturity, Fair Value
Fair Value		213,578
Asset-backed securities
Securities Available-for-Sale, Amortized Cost
Securities not due at a single maturity date	146,391
Total	$ 146,391	241,872
Securities Available-for-Sale, Weighted Average Yield
Securities not due at a single maturity date, Weighted Average Yield (as a percent)	2.15%
Securities Available-for-Sale, Fair Value
Securities not due at a single maturity date	$ 138,407
Fair Value	138,407	231,908
Collateralized loan obligations
Securities Available-for-Sale, Amortized Cost
Securities not due at a single maturity date	102,504
Total	$ 102,504	94,374
Securities Available-for-Sale, Weighted Average Yield
Securities not due at a single maturity date, Weighted Average Yield (as a percent)	3.80%
Securities Available-for-Sale, Fair Value
Securities not due at a single maturity date	$ 101,637
Fair Value	$ 101,637	$ 92,251