Stock-Based Compensation (Details) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2015 USD ($) $ / shares shares	Jun. 30, 2014 USD ($) $ / shares shares	Jun. 30, 2015 USD ($) installment $ / shares shares	Jun. 30, 2014 USD ($) $ / shares shares	Dec. 31, 2014 $ / shares shares	Dec. 31, 2013 $ / shares shares
Stock-based compensation
Gain (Loss) on Sale of Mortgage Loans	$ 5,700	$ 7,400	$ 11,200	$ 12,800
Excess tax benefits from stock-based compensation			$ 1,949	$ 0
Stock option / award activity
Options outstanding at the beginning of the period (in shares) | shares			1,385,497	2,326,201	2,326,201
Exercised (in shares) | shares			(424,684)	(539,733)
Forfeited (in shares) | shares			(36,667)	(15,473)
Options outstanding at the end of the period (in shares) | shares	924,146	1,770,995	924,146	1,770,995	1,385,497	2,326,201
Available for future grant (in shares) | shares	3,516,458	3,348,345	3,516,458	3,348,345	3,515,345
Total shares reserved at the end of period | shares	4,440,604	5,119,340	4,440,604	5,119,340
Options exercisable at the end of period (in shares) | shares	917,479	1,544,332	917,479	1,544,332
WEIGHTED-AVERAGE EXERCISE PRICE
Options outstanding at the beginning of the period (in dollars per option) | $ / shares			$ 23.30	$ 27.02	$ 27.02
Exercised (in dollars per option) | $ / shares			20.67	29.24
Forfeited (in dollars per option) | $ / shares			47.63	21.57
Options outstanding at the end of the period (in dollars per option) | $ / shares	$ 23.55	$ 26.39	23.55	26.39	$ 23.30	$ 27.02
Options exercisable at the end of period (in dollars per option) | $ / shares	$ 23.50	$ 27.49	$ 23.50	$ 27.49
AVERAGE REMAINING CONTRACTUAL LIFE (in years)
SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2			2 years 2 months 12 days	2 years 4 months 24 days	2 years 2 months 26 days	2 years 3 months 18 days
SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2			2 years 2 months 12 days	2 years 4 months 24 days	2 years 2 months 26 days	2 years 3 months 18 days
Weighted average remaining contractual life, Options exercisable at the end of the period (in years)			2 years 2 months 8 days	2 years
AGGREGATE INTRINSIC VALUE
Aggregate intrinsic value, Options outstanding at the end of the period	$ 23,666	$ 30,216	$ 23,666	$ 30,216
Aggregate intrinsic value, Options exercisable at the end of period	23,561	25,571	23,561	25,571
Stock options / awards
Stock-based compensation expense	4,700	4,500	11,500	10,100
Intrinsic values of stock options exercised	979	967	$ 8,900	7,900
Stock options
Stock-based compensation
Vesting period (in years)			3 years
Stock options / awards
Stock-based compensation expense	19	429	$ 220	1,100
2011 Equity and Incentive Plan | Maximum
Stock-based compensation
Expiration period of stock options from date of grant (in years)			7 years
Predecessor plans to the 2011 Equity and Incentive Plan | Minimum
Stock-based compensation
Expiration period of stock options from date of grant (in years)			5 years
Predecessor plans to the 2011 Equity and Incentive Plan | Maximum
Stock-based compensation
Expiration period of stock options from date of grant (in years)			10 years
2004 Non-Employee Director Equity Plan and predecessor plans | Maximum
Stock-based compensation
Expiration period of stock options from date of grant (in years)			10 years
Non-Employee Director Stock Plans
Stock options / awards
Stock-based compensation expense	$ 207	189	$ 454	436
2011 Non-Employee Director Stock Plan (the Director Plan)
Stock-based compensation
Number of shares authorized for issuance to each director | shares			3,000
The maximum period of time that can elapse subsequent to a new director's appointment prior to receipt of an initial award in accordance with the plan			30 days
Stock option / award activity
Available for future grant (in shares) | shares	96,830		96,830		117,830
Restricted stock units
Stock-based compensation
Number of equal annual installments in which awards vest, with performance criteria | installment			3
Restricted stock units | Senior executive officers
Stock-based compensation
Number of equal annual installments in which awards vest, with performance criteria | installment			1
Stock options / awards
Stock-based compensation expense	$ 4,400	$ 3,800	$ 10,900	$ 8,500