Fair Value of Financial Instruments - Quantitative information about unobservable inputs for material assets and liabilities measured using fair value (Details) - USD ($)		3 Months Ended
		Mar. 31, 2017	Dec. 31, 2016	Mar. 31, 2016
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Investment securities held to maturity, estimated fair value		$ 1,142,694,000	$ 1,182,009,000
Fair Value, measurements, recurring | Other assets - SBIC investments
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Other assets -MSRs, fair value		22,553,000
Fair Value, measurements, nonrecurring
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Investment securities held to maturity, estimated fair value		2,013,000
Impaired loans, fair value	[1]	3,510,000		$ 69,032,000
OREO, fair value		25,113,000		17,877,000
Fair Value, Inputs, Level 3
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Investment securities held to maturity, estimated fair value		1,142,694,000	$ 1,182,009,000
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Other Trading Assets
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Other trading asset, fair value		819,000
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Interest rate contracts
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Interest rate contracts, fair value		3,177,000
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Other assets - MSRs
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Other assets -MSRs, fair value		$ 50,776,000
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Minimum | Other Trading Assets | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Prepayment rate		5.80%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Minimum | Interest rate contracts | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Closing rate		18.60%
Cap grid rate		0.20%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Minimum | Other assets - MSRs | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Prepayment rate		0.80%
Cost to service		$ 65
Discount rate		6.60%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Maximum | Other Trading Assets | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Prepayment rate		11.00%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Maximum | Interest rate contracts | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Closing rate		99.10%
Cap grid rate		2.20%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Maximum | Other assets - MSRs | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Prepayment rate		33.50%
Cost to service		$ 4,000
Discount rate		19.20%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Average | Other Trading Assets | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Default rate		10.20%
Prepayment rate		8.00%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Average | Interest rate contracts | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Closing rate		65.60%
Cap grid rate		1.10%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Average | Other assets - MSRs | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Prepayment rate		6.60%
Cost to service		$ 76
Discount rate		8.70%
Fair Value, Inputs, Level 3 | Fair Value, measurements, recurring | Average | Other assets - SBIC investments | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Transaction price		0.00%
Fair Value, Inputs, Level 3 | Fair Value, measurements, nonrecurring
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Investment securities held to maturity, estimated fair value		$ 2,013,000
Impaired loans, fair value	[1]	3,510,000		69,032,000
OREO, fair value		$ 25,113,000		$ 17,877,000
Fair Value, Inputs, Level 3 | Fair Value, measurements, nonrecurring | Minimum | Impaired loans | Appraised value
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Appraised value rate		0.00%
Fair Value, Inputs, Level 3 | Fair Value, measurements, nonrecurring | Maximum | Impaired loans | Appraised value
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Appraised value rate		80.00%
Fair Value, Inputs, Level 3 | Fair Value, measurements, nonrecurring | Average | Investment securities held to maturity | Discounted cash flow
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Default rate		4.80%
Loss severity rate		70.60%
Prepayment rate		5.10%
Fair Value, Inputs, Level 3 | Fair Value, measurements, nonrecurring | Average | Impaired loans | Appraised value
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Appraised value rate		26.70%
Fair Value, Inputs, Level 3 | Fair Value, measurements, nonrecurring | Average | OREO | Appraised value
Fair Value Inputs, Liabilities, Quantitative Information [Line Items]
Appraised value rate	[2]	8.00%

[1] Total gains (losses) represent charge-offs on impaired loans for which adjustments are based on the appraised value of the collateral.

[2] epresents discount to appraised value for estimated costs to sell.