Fair Value Measurements (Fair Value of Assets on a Recurring Basis) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	$ 1,303,381		$ 553,731
Loan servicing rights	41,928	$ 0	0
US Treasury securities [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	5,801		5,765
Government sponsored agencies [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	224,038		194,989
State and political subdivisions [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	305,537		15,120
Residential mortgage-backed securities [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	303,398		187,768
Collateralized mortgage obligations [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	343,739		132,230
Corporate bonds [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	96,085		14,627
Preferred stock and trust preferred securities[Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	24,783		3,232
Recurring [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	1,303,381		553,731
Loans held-for-sale	276,061		10,327
Loan servicing rights	41,928
Total derivatives	17,196		2,018
Total assets measured at fair value on a recurring basis	1,638,566		566,076
Total derivatives	15,970		1,979
Total liabilities at fair value	15,970		1,979
Recurring [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	5,801		5,765
Loans held-for-sale	0		0
Loan servicing rights	0
Total derivatives	0		0
Total assets measured at fair value on a recurring basis	5,801		5,765
Total derivatives	0		0
Total liabilities at fair value	0		0
Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	1,297,580		547,966
Loans held-for-sale	276,061		10,327
Loan servicing rights	0
Total derivatives	17,196		2,018
Total assets measured at fair value on a recurring basis	1,590,837		560,311
Total derivatives	15,970		1,979
Total liabilities at fair value	15,970		1,979
Recurring [Member] | Significant Unobservable Inputs (Level 3) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Loans held-for-sale	0		0
Loan servicing rights	41,928
Total derivatives	0		0
Total assets measured at fair value on a recurring basis	41,928		0
Total derivatives	0		0
Total liabilities at fair value	0		0
Recurring [Member] | Customer-initiated derivatives [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	12,250
Total derivatives	12,787
Recurring [Member] | Customer-initiated derivatives [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	0
Total derivatives	0
Recurring [Member] | Customer-initiated derivatives [Member] | Significant Other Observable Inputs (Level 2) [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	12,250
Total derivatives	12,787
Recurring [Member] | Customer-initiated derivatives [Member] | Significant Unobservable Inputs (Level 3) [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	0
Total derivatives	0
Recurring [Member] | Forward contracts related to mortgage loans to be delivered for sale [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	89		144
Total derivatives	944		57
Recurring [Member] | Forward contracts related to mortgage loans to be delivered for sale [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Total derivatives	0		0
Recurring [Member] | Forward contracts related to mortgage loans to be delivered for sale [Member] | Significant Other Observable Inputs (Level 2) [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	89		144
Total derivatives	944		57
Recurring [Member] | Forward contracts related to mortgage loans to be delivered for sale [Member] | Significant Unobservable Inputs (Level 3) [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Total derivatives	0		0
Recurring [Member] | Interest rate lock commitments [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	2,674		42
Total derivatives	56		90
Recurring [Member] | Interest rate lock commitments [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Total derivatives	0		0
Recurring [Member] | Interest rate lock commitments [Member] | Significant Other Observable Inputs (Level 2) [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	2,674		42
Total derivatives	56		90
Recurring [Member] | Interest rate lock commitments [Member] | Significant Unobservable Inputs (Level 3) [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Total derivatives	0		0
Recurring [Member] | Power Equity CD [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	2,183		1,832
Total derivatives	2,183		1,832
Recurring [Member] | Power Equity CD [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Total derivatives	0		0
Recurring [Member] | Power Equity CD [Member] | Significant Other Observable Inputs (Level 2) [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	2,183		1,832
Total derivatives	2,183		1,832
Recurring [Member] | Power Equity CD [Member] | Significant Unobservable Inputs (Level 3) [Member]
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Total derivatives	0		0
Recurring [Member] | US Treasury securities [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	5,801		5,765
Recurring [Member] | US Treasury securities [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	5,801		5,765
Recurring [Member] | US Treasury securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring [Member] | US Treasury securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring [Member] | Government sponsored agencies [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	224,038		194,989
Recurring [Member] | Government sponsored agencies [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring [Member] | Government sponsored agencies [Member] | Significant Other Observable Inputs (Level 2) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	224,038		194,989
Recurring [Member] | Government sponsored agencies [Member] | Significant Unobservable Inputs (Level 3) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring [Member] | State and political subdivisions [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	305,537		15,120
Recurring [Member] | State and political subdivisions [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring [Member] | State and political subdivisions [Member] | Significant Other Observable Inputs (Level 2) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	305,537		15,120
Recurring [Member] | State and political subdivisions [Member] | Significant Unobservable Inputs (Level 3) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring [Member] | Residential mortgage-backed securities [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	303,398		187,768
Recurring [Member] | Residential mortgage-backed securities [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring [Member] | Residential mortgage-backed securities [Member] | Significant Other Observable Inputs (Level 2) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	303,398		187,768
Recurring [Member] | Residential mortgage-backed securities [Member] | Significant Unobservable Inputs (Level 3) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring [Member] | Collateralized mortgage obligations [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	343,739		132,230
Recurring [Member] | Collateralized mortgage obligations [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring [Member] | Collateralized mortgage obligations [Member] | Significant Other Observable Inputs (Level 2) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	343,739		132,230
Recurring [Member] | Collateralized mortgage obligations [Member] | Significant Unobservable Inputs (Level 3) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring [Member] | Corporate bonds [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	96,085		14,627
Recurring [Member] | Corporate bonds [Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring [Member] | Corporate bonds [Member] | Significant Other Observable Inputs (Level 2) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	96,085		14,627
Recurring [Member] | Corporate bonds [Member] | Significant Unobservable Inputs (Level 3) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring [Member] | Preferred stock and trust preferred securities[Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	24,783		3,232
Recurring [Member] | Preferred stock and trust preferred securities[Member] | Quoted Prices In Active Markets for Identical Assets (Level 1) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring [Member] | Preferred stock and trust preferred securities[Member] | Significant Other Observable Inputs (Level 2) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	24,783		3,232
Recurring [Member] | Preferred stock and trust preferred securities[Member] | Significant Unobservable Inputs (Level 3) [Member]
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	$ 0		$ 0