Loans Receivable - Purchased Credit Impaired Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016
Financing Receivable, Impaired [Line Items]
Outstanding Principal	$ 62,770	$ 71,731
Recorded Investment	55,779	64,448
Commercial Business
Financing Receivable, Impaired [Line Items]
Outstanding Principal	48,058	55,743
Recorded Investment	41,147	48,650
Commercial Business | Commercial and Industrial
Financing Receivable, Impaired [Line Items]
Outstanding Principal	12,318	13,067
Recorded Investment	8,427	9,317
Commercial Business | Owner-occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Outstanding Principal	17,088	17,639
Recorded Investment	15,506	15,973
Commercial Business | Non-owner Occupied Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Outstanding Principal	18,652	25,037
Recorded Investment	17,214	23,360
One-to-four Family Residential
Financing Receivable, Impaired [Line Items]
Outstanding Principal	4,699	5,120
Recorded Investment	4,498	4,905
Real Estate Construction and Land Development
Financing Receivable, Impaired [Line Items]
Outstanding Principal	5,469	5,572
Recorded Investment	4,539	4,611
Real Estate Construction and Land Development | One-to-four Family Real Estate Construction
Financing Receivable, Impaired [Line Items]
Outstanding Principal	2,880	2,958
Recorded Investment	2,069	2,123
Real Estate Construction and Land Development | Five or More Family Residential and Commercial Properties
Financing Receivable, Impaired [Line Items]
Outstanding Principal	2,589	2,614
Recorded Investment	2,470	2,488
Consumer
Financing Receivable, Impaired [Line Items]
Outstanding Principal	4,544	5,296
Recorded Investment	$ 5,595	$ 6,282