Fair Value (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012
Fair value
Interest rate threshold used in determination of accounting for loans underlying mortgage servicing rights (as a percent)	4.50%
Assets:
Short-term investments at fair value	$ 127,487	$ 53,164
Mortgage loans held for sale at fair value	530,248	448,384
Mortgage servicing rights at fair value	26,768	19,798
Derivative assets:
Total derivative assets before netting	43,448	28,381
Netting	(19,382)	(1,091)
Total derivative assets	24,066	27,290
Derivative liabilities:
Total derivative liabilities before netting	48,443	2,294
Netting	(42,667)	(1,785)
Total derivative liabilities	5,776	509
PMT
Assets:
Investment in PMT	1,701	1,897
Recurring basis | Level 1
Assets:
Short-term investments at fair value	127,487	53,164
Derivative assets:
Total assets	129,188	55,061
Recurring basis | Level 1 | PMT
Assets:
Investment in PMT	1,701	1,897
Recurring basis | Level 2
Assets:
Mortgage loans held for sale at fair value	526,063	448,384
Derivative assets:
Total derivative assets before netting	21,731	4,430
Total derivative assets	21,731	4,430
Total assets	547,794	452,814
Derivative liabilities:
Total derivative liabilities before netting	48,284	2,283
Total derivative liabilities	48,284	2,283
Total liabilities	48,284
Recurring basis | Level 2 | Forward contracts | Purchases
Derivative assets:
Total derivative assets before netting	21,226	1,645
Derivative liabilities:
Total derivative liabilities before netting	215	389
Recurring basis | Level 2 | Forward contracts | Sales
Derivative assets:
Total derivative assets before netting	505	1,818
Derivative liabilities:
Total derivative liabilities before netting	48,069	1,894
Recurring basis | Level 2 | MBS put options
Derivative assets:
Total derivative assets before netting		967
Recurring basis | Level 3
Assets:
Mortgage loans held for sale at fair value	4,185
Mortgage servicing rights at fair value	26,768	19,798
Derivative assets:
Total derivative assets before netting	21,717	23,951
Total derivative assets	21,717	23,951
Total assets	52,670	43,749
Derivative liabilities:
Excess servicing spread financing at fair value	2,857
Total derivative liabilities before netting	159	11
Total derivative liabilities	159	11
Total liabilities	3,016
Recurring basis | Level 3 | Interest rate lock commitments
Derivative assets:
Total derivative assets before netting	21,717	23,951
Derivative liabilities:
Total derivative liabilities before netting	159	11
Recurring basis | Total
Assets:
Short-term investments at fair value	127,487	53,164
Mortgage loans held for sale at fair value	530,248	448,384
Mortgage servicing rights at fair value	26,768	19,798
Derivative assets:
Total derivative assets before netting	43,448	28,381
Netting	(19,382)	(1,091)
Total derivative assets	24,066	27,290
Total assets	710,270	550,533
Derivative liabilities:
Excess servicing spread financing at fair value	2,857
Total derivative liabilities before netting	48,443	2,294
Netting	(42,667)	(1,785)
Total derivative liabilities	5,776	509
Total liabilities	8,633
Recurring basis | Total | PMT
Assets:
Investment in PMT	1,701	1,897
Recurring basis | Total | Interest rate lock commitments
Derivative assets:
Total derivative assets before netting	21,717	23,951
Derivative liabilities:
Total derivative liabilities before netting	159	11
Recurring basis | Total | Forward contracts | Purchases
Derivative assets:
Total derivative assets before netting	21,226	1,645
Derivative liabilities:
Total derivative liabilities before netting	215	389
Recurring basis | Total | Forward contracts | Sales
Derivative assets:
Total derivative assets before netting	505	1,818
Derivative liabilities:
Total derivative liabilities before netting	48,069	1,894
Recurring basis | Total | MBS put options
Derivative assets:
Total derivative assets before netting		$ 967